UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM N-CSR

                   CERTIFIED SHAREHOLDER REPORT OF REGISTERED
                        MANAGEMENT INVESTMENT COMPANIES



		Investment Company Act file number 811-21321

                          Pioneer Municipal High Income Trust
               (Exact name of registrant as specified in charter)


                       60 State Street, Boston, MA 02109
              (Address of principal executive offices) (ZIP code)


            Terrence J. Cullen, Pioneer Investment Management, Inc.,
                       60 State Street, Boston, MA 02109
                    (Name and address of agent for service)


Registrant's telephone number, including area code:  (617) 742-7825


Date of fiscal year end:  April 30


Date of reporting period:  May 1, 2016 through April 30, 2017


Form N-CSR is to be used by management investment companies to file reports with
the Commission not later than 10 days after the transmission to stockholders of
any report that is required to be transmitted to stockholders under Rule 30e-1
under the Investment Company Act of 1940 (17 CFR 270.30e-1).  The Commission may
use the information provided on Form N-CSR in its regulatory, disclosure review,
inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-CSR,
and the Commission will make this information public. A registrant is not
required to respond to the collection of information contained in Form N-CSR
unless the Form displays a currently valid Office of Management and Budget
("OMB") control number. Please direct comments concerning the accuracy of the
information collection burden estimate and any suggestions for reducing the
burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW,
Washington, DC 20549-0609.  The OMB has reviewed this collection of information
under the clearance requirements of 44 U.S.C. ss. 3507.


ITEM 1. REPORTS TO STOCKHOLDERS.


                        Pioneer Municipal High
                        Income Trust

--------------------------------------------------------------------------------
                        Annual Report | April 30, 2017
--------------------------------------------------------------------------------

                        Ticker Symbol:   MHI

                        [LOGO] PIONEER
                               Investments(R)


                      visit us: us.pioneerinvestments.com


Table of Contents


                                                                           
President's Letter                                                             2

Portfolio Management Discussion                                                4

Portfolio Summary                                                             12

Prices and Distributions                                                      13

Performance Update                                                            14

Schedule of Investments                                                       15

Financial Statements                                                          25

Financial Highlights                                                          28

Notes to Financial Statements                                                 30

Report of Independent Registered Public Accounting Firm                       38

Approval of New and Interim Management Agreements                             40

Trustees, Officers and Service Providers                                      48


                 Pioneer Municipal High Income Trust | Annual Report | 4/30/17 1


President's Letter

After an overall strong year for leading market indices in 2016, U.S. markets
continued to generate positive returns over the first calendar quarter of 2017,
with so-called "risk" assets, such as equities and credit-sensitive bonds,
posting solid gains. In the first quarter, U.S. equities, as measured by the
Standard & Poor's 500 Index, returned slightly more than 6%, while high-yield
securities dominated bond market performance.

The transfer of power in Washington, D.C. in January had little or no effect on
the markets in the first quarter, as the post-election momentum we witnessed
late in the fourth quarter of 2016 slowed only when oil prices slumped in March,
due to both higher-than-expected inventories and concerns over whether OPEC
(Organization of Petroleum Exporting Countries) would continue its supply cuts
in June. Not even the Federal Reserve System's (the Fed's) highly anticipated
rate hike during the month of March, its second in three months, nor Britain's
trigger of Article 50 to begin the "Brexit" process caused any dramatic sell-off
of risk assets.

While U.S. gross domestic product (GDP) did slow in the first quarter, the
expectation is for GDP to accelerate in the second quarter, with a strong
consumer leading the way. Pioneer believes the U.S. economy may lead all
developed nations in 2017, with GDP growth in excess of 2% for the year.
President Trump has proposed decidedly pro-business policies, such as lower
taxes, higher infrastructure spending, and less regulation, though we believe
the economy may realize the benefits of those policies, if enacted, more so in
2018 than in 2017. Conversely, the effects of the President's potentially
restrictive trade policies could offset some of the benefits of the pro-growth
fiscal policies.

Even so, we believe solid domestic employment figures should continue to support
consumption and the housing market, and that stronger corporate profits and
increased government spending may contribute to economic growth in 2018 and
beyond. Increasing global Purchasing Manager Indices (PMIs) suggest that growth
in global economies is also improving. (PMIs are used to measure the economic
health of the manufacturing sector.)

There are, as always, some risks to our outlook. First, the market already has
priced in a good deal of the Trump economic reform platform, and that could lead
to near-term disappointment if Congressional follow-through does not happen this
year. The future of the Affordable Care Act is another potential concern. The
first attempt to repeal/replace it failed, but any new proposed

2 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


legislation will undoubtedly have an effect on the health care sector, one of
the largest segments of the U.S. economy. Geopolitical risks, of course, remain
a potential headwind, given ongoing strife in the Middle East and renewed
tensions on the Korean Peninsula.

While our current outlook is generally optimistic, conditions can and often do
change, and while passive investment strategies may have a place in one's
overall portfolio, it is our view that all investment decisions are active
choices.

Throughout Pioneer's history, we have believed in the importance of active
management. The active decisions to invest in equities or fixed-income
securities are made by a team of experienced investment professionals focusing
on identifying value across global markets using proprietary research, careful
risk management, and a long-term perspective. We believe our shareowners can
benefit from the experience and tenure of our investment teams as well as the
insights generated from our extensive research process.

As always, and particularly during times of market uncertainty, we encourage you
to work with your financial advisor to develop an overall investment plan that
addresses both your short- and long-term goals, and to implement such a plan in
a disciplined manner.

We greatly appreciate the trust you have placed in us and look forward to
continuing to serve you in the future.

Sincerely,

/s/ Lisa M. Jones

Lisa M. Jones
President and CEO
Pioneer Investment Management USA Inc.
April 30, 2017

Any information in this shareowner report regarding market or economic trends or
the factors influencing the Trust's historical or future performance are
statements of opinion as of the date of this report. Past performance is no
guarantee of future results.

                 Pioneer Municipal High Income Trust | Annual Report | 4/30/17 3


Portfolio Management Discussion | 4/30/17

Municipal bonds generated modest returns over the 12-month period ended April
30, 2017, with higher-yielding, lower-quality debt outperforming
investment-grade municipals. In the following interview, David Eurkus and
Jonathan Chirunga discuss the factors that influenced the performance of Pioneer
Municipal High Income Trust during the 12-month period. Mr. Eurkus, Director of
Municipals, a senior vice president and a portfolio manager at Pioneer, and Mr.
Chirunga, a vice president and a portfolio manager at Pioneer, are responsible
for the day-to-day management of the Trust.

Q    How did the Trust perform during the 12-month period ended April 30, 2017?

A    Pioneer Municipal High Income Trust returned -0.45% at net asset value and
     -11.83% at market price during the 12-month period ended April 30, 2017.
     During the same 12-month period, the Trust's benchmarks, the Bloomberg
     Barclays U.S. Municipal High Yield Bond Index and the Bloomberg Barclays
     Municipal Bond Index, returned 4.38% and 0.14%, respectively. The Bloomberg
     Barclays U.S. Municipal High Yield Bond Index is an unmanaged measure of
     the performance of lower-rated municipal bonds, while the Bloomberg
     Barclays Municipal Bond Index is an unmanaged measure of the performance of
     investment-grade municipal bonds. Unlike the Trust, the two indices do not
     use leverage. While use of leverage increases investment opportunity, it
     also increases investment risk.

     During the same 12-month period, the average return (at market price) of
     the 11 closed end funds in Lipper's High Yield Municipal Debt Closed End
     Funds category (which may or may not be leveraged) was -1.70%.

     The shares of the Trust were selling at a 7.6% discount to net asset value
     at the end of the period on April 30, 2017. Comparatively, the shares of
     the Trust were selling at a 4.3% premium to net asset value on April 30,
     2016, the end of the Trust's previous annual reporting period.

     On April 30, 2017, the standardized 30-day SEC yield of the Trust's shares
     was 3.35%*.

*    The 30-day SEC yield is a standardized formula that is based on the
     hypothetical annualized earning power (investment income only) of the
     Trust's portfolio securities during the period indicated.

4 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Q    How would you describe the investment environment in the municipal bond
     market during the 12-month period ended April 30, 2017?

A    The 12 months saw a contrasting series of investment backdrops in the tax-
     exempt municipal bond market. The period began in May 2016, with both
     investment-grade and high-yield municipal securities performing well,
     helped by declining interest rates and optimistic expectations about
     sustained economic growth. The generally supportive environment persisted
     until early summer 2016, when the Commonwealth of Puerto Rico announced
     that it would default on some of its general obligation debt.

     The news had a particularly strong effect on the high-yield municipal
     market, as Puerto Rico-issued debt, at the time, accounted for
     approximately 23% of the assets represented in the Bloomberg Barclays U.S.
     Municipal High Yield Bond Index. Following the default announcement, those
     weights adjusted, and Puerto Rico's representation in that index dropped to
     slightly less than 13%. After a brief period of high volatility, however,
     all Puerto Rico-related debt began outperforming. The bounce-back occurred
     because negotiations between bondholders and the Commonwealth signaled a
     higher restructuring recovery rate as part of any potential settlement.
     Debt of other well-known distressed borrowers, including the State of
     Illinois, the City of Chicago, and the Chicago Board of Education, also
     gained ground.

     Demand for municipal bonds persisted over the subsequent weeks, until
     market volatility spiked again with the presidential election victory of
     Republican Donald J. Trump in November 2016, and the successful effort of
     Republicans to retain control of both houses of Congress. Mr. Trump had
     campaigned on a pro-growth fiscal platform, which included proposals to cut
     corporate and individual income tax rates, reduce government regulation,
     and increase government spending on infrastructure. However, while the
     equity market shot up after the election on the prospects of faster
     economic growth, the bond market reacted differently. Given that an
     accelerating economy would likely increase inflationary pressures and
     possibly encourage the U.S. Federal Reserve System (the Fed) to raise the
     influential Federal funds rate sooner and more frequently than anticipated,
     market interest rates jumped, which undermined the prices of most bonds,
     especially government bonds and investment-grade securities that tend to be
     more sensitive to the economic cycle. The municipal market struggled even
     more, due to concerns that any reduction of personal income tax rates

                 Pioneer Municipal High Income Trust | Annual Report | 4/30/17 5


     by the U.S. government would make municipal bonds less attractive. In
     addition, there was speculation that any tax reform package might result in
     the loss of the exemption of municipal bond interest from Federal income
     taxes. In that environment, municipal bond prices declined sharply in late
     November and December 2016, undercutting the gains made earlier in 2016. In
     early 2017, however, investors began to believe that the municipal bond
     market had over-corrected in reaction to the election results, and prices
     began to recover.

     Early congressional attempts to change the Affordable Care Act (ACA)
     foundered, leading to doubts about the Republicans' ability to implement
     other elements of the president's platform, including tax reform and
     infrastructure spending. The uncertainty helped sustain the rally in the
     municipal bond market through the final three months of the Trust's fiscal
     year (February, March and April of 2017). In the late-period rally, tobacco
     bonds, backed by tobacco Master Settlement Agreement revenues, performed
     particularly well. Tobacco bonds had underperformed in the immediate
     post-election market downturn, as many investors began selling their most
     easily tradable securities.

     Over the full 12-month period, both investment-grade and high-yield
     municipal bonds turned in positive performance, with high-yield municipals
     outperforming investment grade by a solid margin.

Q    What factors affected the Trust's benchmark-relative performance during the
     12-month period ended April 30, 2017?

A    The Trust's exposure to investment-grade municipal bonds (rated "BBB-" or
     higher by Standard & Poor's) held back benchmark-relative results during a
     period when market interest rates generally rose. At the end of the period,
     on April 30, 2017, approximately 62% of the securities in the Trust's total
     investment portfolio had investment-grade ratings, which generally are more
     sensitive to rising interest rates. In addition, many issuers of existing
     municipal bonds refinanced their debt to issue new securities at lower
     interest rates - while they still had the opportunity to do so - resulting
     in a loss of current income for the Trust. Moreover, our emphasis on owning
     the debt of financially stable issuers had caused us to severely
     underweight the debt of financially troubled issuers in the Trust's
     portfolio, including Puerto Rico, the State of Illinois, the City of
     Chicago, and the Chicago Board of Education. The underweighted portfolio
     exposures held back benchmark-relative results when those securities
     rallied following the July 2016 Puerto Rican default announcement. At the
     end of the period, on April 30, 2017,

6 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


     Puerto Rican debt accounted for 0.9% of the Trust's total investment
     portfolio, compared with a 12.7% weighting for Puerto Rico in the Bloomberg
     Barclays Bloomberg Barclays U.S. Municipal High Yield Bond Index. (In early
     May 2017, after the end of the Trust's fiscal year, the Commonwealth of
     Puerto Rico filed for bankruptcy protection.) Meanwhile, the Trust's
     portfolio did have more than 14% exposure to the debt of issuers based in
     Illinois as of April 30, 2017, but the allocation was limited to revenue
     bonds - primarily continuing care retirement communities (CCRCs) - and did
     not include the distressed general obligation bonds of the State of
     Illinois, which outperformed during the period.

     On the positive side, security selection tended to help the Trust's
     benchmark-relative performance during the 12-month period, despite the
     negative effects of the portfolio's underweight to the debt of the
     financially troubled issuers mentioned above. The Trust's portfolio fared
     particularly well in late 2016 and the early months of 2017 when high-yield
     municipals rallied and the Trust's benchmark-relative performance improved.
     In addition, our emphasis on holding project revenue bonds in the Trust's
     portfolio proved beneficial for benchmark-relative results. These included
     investments in tobacco bonds, which, as noted earlier, turned in strong
     performance during the late-period rally in the municipal market. At the
     end of the Trust's fiscal year, tobacco bonds represented 7.6% of the
     Trust's total investment portfolio.

     In other sectors, the Trust's exposures to transportation, and education
     and health care bonds also benefited benchmark-relative returns.

     With regard to individual securities, the top three positive contributors
     to the Trust's benchmark-relative performance during the 12-month period
     were (in order): a Washington, D.C. tobacco bond; a "Buckeye" (State of
     Ohio) tobacco bond; and a Massachusetts Development Authority bond.
     Meanwhile, the three primary detractors from the Trust's benchmark-
     relative returns were (in order): a Sanger (Texas) industrial revenue bond;
     an Ohio air quality bond; and a Beaver County (Pennsylvania) Industrial
     Development Authority security.

     Throughout the 12 months, we continued to emphasize project revenue bonds
     in the Trust's portfolio, bonds backed by revenues from specific projects
     or agencies. We believe the financial support for such projects and
     agencies is more consistent and predictable than the revenues supporting
     general obligation municipal bonds, which rely principally on state and
     local tax revenues. At the end of the fiscal year, project revenue bonds
     represented almost 90% of the Trust's total investment portfolio.

                 Pioneer Municipal High Income Trust | Annual Report | 4/30/17 7


Q    Did you use any derivatives in managing the Trust's portfolio during the
     12-month period ended April 30, 2017?

A    No. The Trust held no derivative securities during the period.

Q    What factors affected the Trust's yield during the 12-month period ended
     April 30, 2017?

A    We twice reduced the Trust's monthly dividend** distribution during the
     fiscal year. In August 2016, the dividend declined from 7 cents per share
     to 5.75 cents per share, and then dropped to 4.75 cents per share in
     December 2016. Two factors were responsible for the reductions. First, as
     interest rates rose during the period, the Trust's borrowing costs in
     obtaining leverage increased, which cut into the current income available
     for distribution to shareholders. Second, as we mentioned earlier, many
     bonds in the Trust's portfolio refinanced over the period, which also
     reduced current income in the portfolio when lower-yielding securities
     replaced the older bonds that were called.

     In addition, the Trust has drawn on accumulated net investment income in
     paying the Trust's distributions in recent periods, but these reserves may
     be depleted over time.

Q    Did the level of leverage in the Trust change during the 12-month period
     ended April 30, 2017?

A    At the end of the 12-month period on April 30, 2017, 25.9% of the Trust's
     total managed assets were financed by leverage through the issuance of
     preferred shares, compared with 24.8% of the Trust's total managed assets
     at the start of the period on May 1, 2016. Even though there was a slight
     increase in the overall value of leverage due to an increase in the ending
     dividend payable to preferred shareowners, the amount of preferred shares
     outstanding remained the same throughout the period. The increase in the
     percentage of leveraged funds was primarily the result of depreciation in
     the value of the Trust's holdings.

**   Dividends are not guaranteed.

8 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Q    What is your investment outlook?

A    We continue to think the domestic economy should expand steadily during
     2017, with gross domestic product (GDP) growing at an average 2% pace for
     the year. The nation's unemployment rate fell to 4.4% in April, and we
     think it could fall even more. While some signs of weakness in housing
     starts and automobile sales have recently appeared, we think the economy is
     strong and resilient enough to continue to grow. The Fed has raised the
     Federal fund rate twice in recent months - in December 2016 and March 2017
     - and may raise it once or twice more before the end of the calendar year.
     However, we do not expect the rate increases to have a major effect on the
     economy in general, or the financial markets.

     Yield remains an important part of our investment goal, but shareholders
     should be aware that while rising interest rates could increase the
     potential for greater income in the portfolio, they also increase the
     Trust's cost of financing, which, as we saw over the past 12 months, can
     lower the funds available for dividend distributions. In addition, the
     portfolio's income can come under pressure if bond issuers continue to
     refinance older, higher-yielding debt and replace those securities with
     new issues paying lower yields, which also happened during the past 12
     months.

     While we have maintained confidence in the general economy, one uncertainty
     affecting investor sentiment is the question of whether the Trump
     administration can agree with Congress on legislation to reduce and reform
     taxes, increase infrastructure spending, replace or repeal the ACA, and
     continue to deregulate markets. As time passes without major legislation on
     these issues, doubts among market participants could persist.

     In closing, we think the U.S. economic expansion will persist and further
     enhance the overall credit-worthiness of municipal debt issuers. Municipal
     bond prices should improve in an environment where the attractive relative
     values of municipal bonds versus taxable bonds become more apparent to both
     traditional and non-traditional buyers of municipal bonds, and in which an
     improving economy strengthens overall credit quality.

     We believe our emphasis on holding better-financed special revenue bonds in
     the Trust's portfolio may benefit performance over the long term. We intend
     to maintain our focus on a highly diversified*** portfolio of investments
     in securities backed by predictable, reliable revenues.

***  Diversification does not assure a profit nor protect against loss.


                 Pioneer Municipal High Income Trust | Annual Report | 4/30/17 9


Please refer to the Schedule of Investments on pages 15-24 for a full listing of
Trust securities.

All investments are subject to risk, including the possible loss of principal.
In the past several years, financial markets have experienced increased
volatility, depressed valuations, decreased liquidity and heightened
uncertainty. These conditions may continue, recur, worsen or spread.

Investments in high-yield or lower-rated securities are subject to greater-than-
average risk.

The Trust may invest in securities of issuers that are in default or that are in
bankruptcy.

A portion of income may be subject to state, federal, and/or alternative minimum
tax. Capital gains, if any, are subject to a capital gains tax.

When interest rates rise, the prices of debt securities held by the Trust will
generally fall. Conversely, when interest rates fall the prices of debt
securities held by the Trust generally will rise.

Interest rates in the U.S. recently have been historically low, so the Trust
faces a heightened risk that interest rates may rise. A general rise in interest
rates may cause investors to move out of fixed income securities on a large
scale, which could adversely affect the price and liquidity of fixed income
securities.

By concentrating in municipal securities, the Trust is more susceptible to
adverse economic, political or regulatory developments than is a portfolio that
invests more broadly.

Investments in the Trust are subject to possible loss due to the financial
failure of the issuers of the underlying securities and the issuers' inability
to meet their debt obligations.

The Trust may invest up to 20% of its total assets in illiquid securities.
Illiquid securities may be difficult to dispose of at a price reflective of
their value at the times when the Trust believes it is desirable to do so, and
the market price of illiquid securities is generally more volatile than that of
more liquid securities. Illiquid securities are also more difficult to value and
investment of the Trust's assets in illiquid securities may restrict the Trust's
ability to take advantage of market opportunities.

The Trust uses leverage through the issuance of preferred shares. Leverage
creates significant risks, including the risk that the Trust's incremental
income or capital appreciation for investments purchased with the proceeds of
leverage will not be sufficient to cover the cost of the leverage, which may
adversely affect the return for the holders of common shares. Since February of
2008, regularly scheduled auctions for the Trust's preferred shares have failed
and preferred shareowners have not been able to sell their shares at auction.
The Board of Trustees of the Trust has considered, and continues to consider,
this issue.

10 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


The Trust is required to maintain certain regulatory, rating agency and other
asset coverage requirements in connection with its outstanding preferred shares.
In order to maintain required asset coverage levels, the Trust may be required
to alter the composition of its investment portfolio or take other actions, such
as redeeming preferred shares with the proceeds from portfolio transactions, at
what might be inopportune times in the market. Such actions could reduce the net
earnings or returns to holders of the Trust's common shares over time, which is
likely to result in a decrease in the market value of the Trust's shares.

Risks of investing in the Trust are discussed in greater detail in the Trust's
original offering prospectus and in shareowner reports issued from time to time.

These risks may increase share price volatility.

Any information in this shareholder report regarding market or economic trends
or the factors influencing the Fund's historical or future performance are
statements of opinion as of the date of this report. Past performance is no
guarantee of future results.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 11


Portfolio Summary | 4/30/17

Portfolio Diversification
--------------------------------------------------------------------------------
(As a percentage of total investment portfolio)

[THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL]



                                                                        
Revenue Bonds:
Other Revenue                                                              32.2%
Insured Bonds                                                              15.6%
Health Revenue                                                             13.2%
Development Revenue                                                         7.8%
Facilities Revenue                                                          7.8%
Tobacco Revenue                                                             7.6%
Education Revenue                                                           6.6%
Transportation Revenue                                                      3.6%
Water Revenue                                                               2.4%
Airport Revenue                                                             1.9%
Pollution Control Revenue                                                   1.3%


10 Largest Holdings
--------------------------------------------------------------------------------
(As a percentage of long-term holdings)*



                                                                                             
  1. Metropolitan Pier & Exposition Authority, McCormick Place, Series B,
     6/15/22 (NATL Insured)                                                                     4.50%
-----------------------------------------------------------------------------------------------------
  2. State of Washington, Motor Vehicle Sales Tax, Series C, 6/1/22 (NATL Insured)              3.39
-----------------------------------------------------------------------------------------------------
  3. North Texas Tollway Authority, Series F, 5.75%, 1/1/33                                     2.68
-----------------------------------------------------------------------------------------------------
  4. Massachusetts Development Finance Agency, WGBH Foundation, Series A,
     5.75%, 1/1/42 (AMBAC Insured)                                                              2.43
-----------------------------------------------------------------------------------------------------
  5. Lehman Municipal Trust Receipts, RIB, 11.641%, 11/1/39 (144A) (AGM Insured)                2.29
-----------------------------------------------------------------------------------------------------
  6. New York State Dormitory Authority, Series C, 5.0%, 3/15/39                                2.19
-----------------------------------------------------------------------------------------------------
  7. State of Minnesota, Series B, 4.0%, 8/1/27                                                 1.78
-----------------------------------------------------------------------------------------------------
  8. Massachusetts Development Finance Agency, Harvard University, Series A, 5.0%, 7/15/40      1.66
-----------------------------------------------------------------------------------------------------
  9. District of Columbia Tobacco Settlement Financing Corp., Asset-Backed, 6.75%, 5/15/40      1.58
-----------------------------------------------------------------------------------------------------
 10. Buckeye Tobacco Settlement Financing Authority, Asset-Backed, Series A-2, 6.5%, 6/1/47     1.56
-----------------------------------------------------------------------------------------------------


*    This list excludes temporary cash investments. The portfolio is actively
     managed, and current holdings may be different. The holdings listed should
     not be considered recommendations to buy or sell any security listed.

12 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Prices and Distributions | 4/30/17

Market Value per Common Share^
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                                         4/30/17                         4/30/16
--------------------------------------------------------------------------------
                                                                    
         Market Value                     $11.75                          $14.07
--------------------------------------------------------------------------------
         Premium/(Discount)                (7.6)%                          4.3%
--------------------------------------------------------------------------------



Net Asset Value per Common Share^
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                                         4/30/17                         4/30/16
--------------------------------------------------------------------------------
                                                                    
       Net Asset Value                    $12.72                          $13.49
--------------------------------------------------------------------------------


Distributions per Common Share
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                          Net Investment       Short-Term           Long-Term
                              Income          Capital Gains        Capital Gains
--------------------------------------------------------------------------------
                                                              
     5/1/16 - 4/30/17         $0.69               $ --                 $ --
--------------------------------------------------------------------------------


Yields
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                                         4/30/17                         4/30/16
--------------------------------------------------------------------------------
                                                                    
      30-Day SEC Yield                    3.35%                           3.37%
--------------------------------------------------------------------------------


The data shown above represents past performance, which is no guarantee of
future results.

^    Net asset value and market value are published in Barron's on Saturday, The
     Wall Street Journal on Monday and The New York Times on Monday and
     Saturday. Net asset value and market value are published daily on the
     Trust's website at us.pioneerinvestments.com.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 13


Performance Update | 4/30/17

Investment Returns
--------------------------------------------------------------------------------
The mountain chart on the right shows the change in market value, including
reinvestment of dividends and distributions, of a $10,000 investment made in
common shares of Pioneer Municipal High Income Trust during the periods shown,
compared to that of the Bloomberg Barclays Municipal Bond Index and Bloomberg
Barclays U.S. Municipal High Yield Bond Index.



Average Annual Total Returns
(As of April 30, 2017)
--------------------------------------------------------------------------------
                                                   Bloomberg
                                                   Barclays
                                      Bloomberg    U.S.
                                      Barclays     Municipal
              Net                     Municipal    High Yield
              Asset                   Bond         Bond
              Value       Market      Index        Index
Period        (NAV)       Price       (NAV)        (NAV)
--------------------------------------------------------------------------------
                                       
10 years       5.13%        4.95%     4.37%        4.30%
5 years        5.12         1.55      3.16         5.31
1 year        -0.45       -11.83      0.14         4.38
--------------------------------------------------------------------------------


[THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL]

Value of $10,000 Investment



             Pioneer Municipal   Bloomberg Barclays     Bloomberg Barclays U.S.
             High Income Trust   Municipal Bond Index   Municipal High Yield Bond Index
                                               
4/07         $10,000             $10,000                $10,000
4/08         $ 9,772             $10,279                $ 9,335
4/09         $ 7,930             $10,599                $ 7,681
4/10         $11,791             $11,537                $ 9,798
4/11         $11,914             $11,791                $10,125
4/12         $15,006             $13,131                $11,761
4/13         $16,728             $13,812                $13,269
4/14         $16,911             $13,881                $13,051
4/15         $18,068             $14,547                $13,967
4/16         $18,385             $15,317                $14,597
4/17         $16,209             $15,339                $15,236


Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent
month-end performance results. Current performance may be lower or higher than
the performance data quoted.

Performance data shown represents past performance. Past performance is no
guarantee of future results. Investment return and market price will fluctuate,
and your shares may trade below NAV due to such factors as interest rate changes
and the perceived credit quality of borrowers.

Total investment return does not reflect broker sales charges or commissions.
All performance is for common shares of the Trust.

Shares of closed-end funds, unlike open-end funds, are not continuously offered.
There is a one-time public offering and, once issued, shares of closed-end funds
are bought and sold in the open market through a stock exchange and frequently
trade at prices lower than their NAV. NAV per common share is total assets less
total liabilities, which include preferred shares or borrowings, as applicable,
divided by the number of common shares outstanding.

When NAV is lower than market price, dividends are assumed to be reinvested at
the greater of NAV or 95% of the market price. When NAV is higher, dividends are
assumed to be reinvested at prices obtained through open-market purchases under
the Trust's dividend reinvestment plan.

The performance table and graph do not reflect the deduction of fees and taxes
that a shareowner would pay on Trust distributions or the sale of Trust shares.
Had these fees and taxes been reflected, performance would have been lower.

The Bloomberg Barclays Municipal Bond Index is an unmanaged, broad measure of
the municipal bond market. The Bloomberg Barclays High Yield Municipal Bond
Index is unmanaged, totals over $26 billion in market value and maintains over
1,300 securities. Municipal bonds in this index have the following requirements:
maturities of one year or greater, sub investment grade (below Baa or
non-rated), fixed coupon rate, issued after 12/31/90, deal size over $20
million, and maturity size of at least $3 million. Index returns are calculated
monthly, assume reinvestment of dividends and, unlike Trust returns, do not
reflect any fees, expenses or sales charges. The indices do not use leverage. It
is not possible to invest directly in the indices.

14 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Schedule of Investments | 4/30/17



-----------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                    Value
-----------------------------------------------------------------------------------------------------------
                                                                                     
                          TAX EXEMPT OBLIGATIONS -- 133.0% of
                          Net Assets (a)
                          Alabama -- 1.5%
    4,500,000             Huntsville-Redstone Village Special Care Facilities Financing
                          Authority, Redstone Village Project, 5.5%, 1/1/43                $      4,373,100
-----------------------------------------------------------------------------------------------------------
                          Arizona -- 0.7%
    2,250,000             City of Phoenix, AZ, Industrial Development Authority, 3rd &
                          Indian School Assisted Living Project, 5.4%, 10/1/36             $      2,061,293
       24,000             County of Pima, AZ, Industrial Development Authority, Arizona
                          Charter Schools Project, Series C, 6.75%, 7/1/31                           24,047
                                                                                           ----------------
                                                                                           $      2,085,340
-----------------------------------------------------------------------------------------------------------
                          California -- 10.7%
   10,000,000(b)          California County Tobacco Securitization Agency, Capital
                          Appreciation, Stanislaus County Subordinated, Series A,
                          6/1/46                                                           $      1,445,600
    1,450,000             California Enterprise Development Authority, Sunpower
                          Corp., 8.5%, 4/1/31                                                     1,588,170
      650,000             California Municipal Finance Authority, Santa Rosa
                          Academy Project, Series A, 5.75%, 7/1/30                                  696,072
    5,000,000             California Pollution Control Financing Authority, 5.0%,
                          7/1/37 (144A)                                                           5,018,350
    1,740,000             California School Finance Authority, Classical Academies
                          Project, Series A, 7.375%, 10/1/43                                      2,019,635
    1,400,000             California Statewide Communities Development Authority,
                          Lancer Plaza Project, 5.625%, 11/1/33                                   1,467,886
      568,006(c)          California Statewide Communities Development Authority,
                          Microgy Holdings Project, 9.0%, 12/1/38                                         6
    7,885,000(d)          Lehman Municipal Trust Receipts, RIB, 11.641%,
                          11/1/39 (144A) (AGM Insured)                                            8,833,250
    2,000,000(e)          Los Angeles Community College District, Series G,
                          4.0%, 8/1/39                                                            2,075,220
    1,605,000             Los Angeles County Metropolitan Transportation Authority,
                          Series A, 5.0%, 7/1/30                                                  1,958,614
    1,000,000             River Islands Public Financing Authority, Community
                          Facilities, 5.5%, 9/1/45                                                1,058,920
    2,000,000             Tobacco Securitization Authority of Northern California,
                          Asset-Backed, Series A-1, 5.375%, 6/1/38                                1,971,600
    3,000,000             Tobacco Securitization Authority of Southern California,
                          Series A-1, 5.0%, 6/1/37                                                2,999,910
                                                                                           ----------------
                                                                                           $     31,133,233
-----------------------------------------------------------------------------------------------------------
                          Colorado -- 1.3%
    1,500,000             Colorado Educational & Cultural Facilities Authority, Rocky
                          Mountain Classical Academy Project, 8.0%, 9/1/43                 $      1,664,460
    2,000,000             Colorado Health Facilities Authority, Valley View Association
                          Project, 5.25%, 5/15/42                                                 2,004,220
                                                                                           ----------------
                                                                                           $      3,668,680
-----------------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 15


Schedule of Investments | 4/30/17 (continued)



-----------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                    Value
-----------------------------------------------------------------------------------------------------------
                                                                                     
                          Connecticut -- 3.2%
    2,915,000             Mohegan Tribal Finance Authority, 7.0%, 2/1/45 (144A)            $      3,043,289
    5,000,000(e)          State of Connecticut, Series E, 4.0%, 9/1/30                            5,272,000
    1,000,000             Town of Hamden, CT, Whitney Center Project, Series A,
                          7.75%, 1/1/43                                                           1,027,150
                                                                                           ----------------
                                                                                           $      9,342,439
-----------------------------------------------------------------------------------------------------------
                          District of Columbia -- 5.0%
    4,365,000             District of Columbia Tobacco Settlement Financing Corp.,
                          Asset-Backed, 6.5%, 5/15/33                                      $      4,899,451
    6,000,000             District of Columbia Tobacco Settlement Financing Corp.,
                          Asset-Backed, 6.75%, 5/15/40                                            6,097,500
   25,000,000(b)          District of Columbia Tobacco Settlement Financing Corp.,
                          Capital Appreciation, Asset-Backed, Series A, 6/15/46                   3,479,750
                                                                                           ----------------
                                                                                           $     14,476,701
-----------------------------------------------------------------------------------------------------------
                          Florida -- 4.9%
    1,500,000             Alachua County Health Facilities Authority, Terraces Bonita
                          Springs Project, Series A, 8.125%, 11/15/41                      $      1,724,955
    1,500,000             Alachua County Health Facilities Authority, Terraces Bonita
                          Springs Project, Series A, 8.125%, 11/15/46                             1,722,300
    2,260,000(c)          County of Liberty, FL, Twin Oaks Project, 8.25%, 7/1/28                   202,338
    2,500,000(f)          County of Miami-Dade, FL, Aviation Revenue, Series B,
                          5.5%, 10/1/41                                                           2,760,250
    5,000,000             Florida's Turnpike Enterprise, Department of Transportation,
                          Series A, 4.0%, 7/1/34                                                  5,215,300
    1,000,000(f)          Hillsborough County Industrial Development Authority,
                          Various Health Facilities, 8.0%, 8/15/32                                1,164,140
    2,250,000(c)(d)       St. Johns County Industrial Development Authority,
                          Glenmoor Project, Series A, 1.344%, 1/1/49                              1,439,100
      832,581(c)          St. Johns County Industrial Development Authority,
                          Glenmoor Project, Series B, 2.5%, 1/1/49                                        8
                                                                                           ----------------
                                                                                           $     14,228,391
-----------------------------------------------------------------------------------------------------------
                          Georgia -- 2.6%
    2,500,000             Clayton County Development Authority, Delta Air Lines,
                          Series A, 8.75%, 6/1/29                                          $      2,943,775
    4,000,000             Private Colleges & Universities Authority, Emory University,
                          Series A, 5.0%, 10/1/43                                                 4,526,640
                                                                                           ----------------
                                                                                           $      7,470,415
-----------------------------------------------------------------------------------------------------------
                          Idaho -- 1.7%
    5,000,000             Power County Industrial Development Corp., FMC Corp.
                          Project, 6.45%, 8/1/32                                           $      5,008,800
-----------------------------------------------------------------------------------------------------------
                          Illinois -- 14.5%
    2,087,000(d)          Illinois Finance Authority, Clare Oaks Project, Series B,
                          4.0%, 11/15/52                                                   $      1,467,641
    1,305,000(b)          Illinois Finance Authority, Clare Oaks Project,
                          Series C-1, 11/15/52                                                       45,675


The accompanying notes are an integral part of these financial statements.

16 Pioneer Municipal High Income Trust | Annual Report | 4/30/17




-----------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                    Value
-----------------------------------------------------------------------------------------------------------
                                                                                     
                          Illinois -- (continued)
      261,000(b)          Illinois Finance Authority, Clare Oaks Project,
                          Series C-2, 11/15/52                                             $        71,021
      261,000(b)          Illinois Finance Authority, Clare Oaks Project,
                          Series C-3, 11/15/52                                                       44,628
    2,000,000(c)          Illinois Finance Authority, Greenfields of Geneva Project,
                          Series A, 8.125%, 2/15/40                                               1,319,600
    2,500,000(c)          Illinois Finance Authority, Greenfields of Geneva Project,
                          Series A, 8.25%, 2/15/46                                                1,649,500
    2,000,000             Illinois Finance Authority, Northwestern Memorial Hospital,
                          Series A, 6.0%, 8/15/39                                                 2,197,660
    2,500,000             Illinois Finance Authority, Roosevelt University Project,
                          6.5%, 4/1/39                                                            2,645,950
    3,865,000(f)          Illinois Finance Authority, Swedish Covenant, Series A,
                          6.0%, 8/15/38                                                           4,369,460
    1,700,000             Illinois Finance Authority, The Admiral at the Lake Project,
                          Series A, 7.625%, 5/15/25                                               1,886,592
      600,000             Illinois Finance Authority, The Admiral at the Lake Project,
                          Series A, 7.75%, 5/15/30                                                  666,168
    2,000,000             Illinois Finance Authority, The Admiral at the Lake Project,
                          Series A, 8.0%, 5/15/40                                                 2,222,640
    3,200,000             Illinois Finance Authority, The Admiral at the Lake Project,
                          Series A, 8.0%, 5/15/46                                                 3,547,616
    1,485,000(b)(g)       Metropolitan Pier & Exposition Authority, McCormick Place,
                          Series B, 6/15/22 (NATL Insured)                                        1,732,119
   15,395,000(b)          Metropolitan Pier & Exposition Authority, McCormick Place,
                          Series B, 6/15/22 (NATL Insured)                                       17,339,080
    1,030,000             Southwestern Illinois Development Authority, Village of
                          Sauget Project, 5.625%, 11/1/26                                           910,335
                                                                                           ----------------
                                                                                           $     42,115,685
-----------------------------------------------------------------------------------------------------------
                          Indiana -- 1.8%
      250,000             City of Carmel, IN, Barrington Carmel Project, Series A,
                          7.0%, 11/15/32                                                   $        271,510
      750,000             City of Carmel, IN, Barrington Carmel Project, Series A,
                          7.125%, 11/15/42                                                          815,243
      500,000             City of Carmel, IN, Barrington Carmel Project, Series A,
                          7.125%, 11/15/47                                                          542,245
    3,570,000(f)          Vigo County Hospital Authority, Union Hospital, Inc., 5.8%,
                          9/1/47 (144A)                                                           3,629,262
                                                                                           ----------------
                                                                                           $      5,258,260
-----------------------------------------------------------------------------------------------------------
                          Kentucky -- 1.9%
    5,000,000             Kentucky Economic Development Finance Authority,
                          Owensboro Medical Health System, Series A, 6.375%,
                          6/1/40                                                           $      5,555,500
-----------------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 17


Schedule of Investments | 4/30/17 (continued)



-----------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                    Value
-----------------------------------------------------------------------------------------------------------
                                                                                     
                          Louisiana -- 3.1%
    2,260,000             Jefferson Parish Hospital Service District No. 2, East
                          Jefferson General Hospital, 6.375%, 7/1/41                       $      2,388,232
    1,500,000             Louisiana Local Government Environmental Facilities &
                          Community Development Authority, Westlake Chemical
                          Corp. Project, 6.75%, 11/1/32                                           1,532,880
    1,380,000(f)          Louisiana Public Facilities Authority, Ochsner Clinic
                          Foundation Project, Series A, 5.5%, 5/15/47                             1,383,064
    3,620,000             Louisiana Public Facilities Authority, Ochsner Clinic
                          Foundation Project, Series A, 5.5%, 5/15/47                             3,633,249
                                                                                           ----------------
                                                                                           $      8,937,425
-----------------------------------------------------------------------------------------------------------
                          Maine -- 2.3%
    1,500,000             Maine Health & Higher Educational Facilities Authority,
                          Maine General Medical Center, 7.5%, 7/1/32                       $      1,697,130
    4,480,000             Maine Turnpike Authority, Series A, 5.0%, 7/1/42                        5,015,808
                                                                                           ----------------
                                                                                           $      6,712,938
-----------------------------------------------------------------------------------------------------------
                          Maryland -- 0.6%
    1,480,000             Maryland Health & Higher Educational Facilities Authority,
                          City Neighbors, Series A, 6.75%, 7/1/44                          $      1,616,426
-----------------------------------------------------------------------------------------------------------
                          Massachusetts -- 9.7%
    7,000,000(b)          Massachusetts Bay Transportation Authority,
                          Series A, 7/1/28                                                 $      4,889,990
    5,000,000             Massachusetts Development Finance Agency, Harvard
                          University, Series A, 5.0%, 7/15/40                                     6,389,650
    1,000,000             Massachusetts Development Finance Agency, Linden
                          Ponds, Inc., Series A, 4.68%, 11/15/21 (144A)                           1,010,000
      975,158             Massachusetts Development Finance Agency, Linden
                          Ponds, Inc., Series A-1, 5.5%, 11/15/46                                   889,880
    1,000,000             Massachusetts Development Finance Agency, Partners
                          Healthcare System, 4.0%, 7/1/41                                         1,016,880
    7,100,000             Massachusetts Development Finance Agency, WGBH
                          Foundation, Series A, 5.75%, 1/1/42 (AMBAC Insured)                     9,353,327
      380,000             Massachusetts Educational Financing Authority, Series I,
                          6.0%, 1/1/28                                                              401,436
    3,100,000             Massachusetts Health & Educational Facilities Authority,
                          Massachusetts Institute of Technology, Series K,
                          5.5%, 7/1/32                                                            4,083,661
                                                                                           ----------------
                                                                                           $     28,034,824
-----------------------------------------------------------------------------------------------------------
                          Michigan -- 3.0%
      895,000(c)          Doctor Charles Drew Academy, Certificate of Participation,
                          5.7%, 11/1/36                                                    $         44,750
    2,640,000             Michigan State University, Series A, 5.0%, 8/15/41                      2,982,830
    6,100,000             Michigan Tobacco Settlement Finance Authority, Series A,
                          6.0%, 6/1/48                                                            5,723,813
                                                                                           ----------------
                                                                                           $      8,751,393
-----------------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

18 Pioneer Municipal High Income Trust | Annual Report | 4/30/17




-----------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                    Value
-----------------------------------------------------------------------------------------------------------
                                                                                     
                          Minnesota -- 4.1%
    2,000,000             Bloomington Port Authority, Radisson Blu Mall of America,
                          9.0%, 12/1/35                                                    $      2,112,120
    2,300,000             City of Rochester, MN, Mayo Clinic, Series B,
                          5.0%, 11/15/35                                                          2,850,045
    6,000,000(e)          State of Minnesota, Series B, 4.0%, 8/1/27                              6,867,180
                                                                                           ----------------
                                                                                           $     11,829,345
-----------------------------------------------------------------------------------------------------------
                          Mississippi -- 0.1%
      380,000(d)          Mississippi Business Finance Corp., Chevron USA, Inc.,
                          Project, Series B, 0.89%, 12/1/30                                $        380,000
-----------------------------------------------------------------------------------------------------------
                          Montana -- 0.0%+
    1,600,000(c)          Two Rivers Authority, Inc., 7.375%, 11/1/27                      $         47,328
-----------------------------------------------------------------------------------------------------------
                          New Jersey -- 2.1%
    3,000,000             New Jersey Economic Development Authority, Continental
                          Airlines, 5.25%, 9/15/29                                         $      3,245,820
    2,500,000             New Jersey Economic Development Authority, Continental
                          Airlines, 5.75%, 9/15/27                                                2,717,350
                                                                                           ----------------
                                                                                           $      5,963,170
-----------------------------------------------------------------------------------------------------------
                          New Mexico -- 1.5%
    1,500,000             County of Otero, NM, Otero County Jail Project,
                          6.0%, 4/1/23                                                     $      1,444,995
    2,960,000             County of Otero, NM, Otero County Jail Project,
                          6.0%, 4/1/28                                                            2,769,998
                                                                                           ----------------
                                                                                           $      4,214,993
-----------------------------------------------------------------------------------------------------------
                          New York -- 5.6%
    2,000,000             Hempstead Local Development Corp., Molloy College
                          Project, 5.75%, 7/1/39                                           $      2,154,140
    1,000,000(f)          New York State Dormitory Authority, Orange Medical Center,
                          6.125%, 12/1/29                                                         1,080,600
    7,500,000             New York State Dormitory Authority, Series C,
                          5.0%, 3/15/39                                                           8,450,850
    1,500,000             New York State Dormitory Authority, Trustees of Columbia
                          University, 5.0%, 10/1/45                                               1,967,925
    2,497,540             Westchester County Healthcare Corp., Series A,
                          5.0%, 11/1/44                                                           2,637,977
                                                                                           ----------------
                                                                                           $     16,291,492
-----------------------------------------------------------------------------------------------------------
                          North Dakota -- 1.0%
    2,525,000(f)          County of Burleigh, ND, St. Alexius Medical Center,
                          5.0%, 7/1/38                                                     $      2,952,482
-----------------------------------------------------------------------------------------------------------
                          Ohio -- 5.9%
    1,325,000             Buckeye Tobacco Settlement Financing Authority,
                          Asset-Backed, Series A-2, 5.75%, 6/1/34                          $      1,264,090
    2,500,000             Buckeye Tobacco Settlement Financing Authority,
                          Asset-Backed, Series A-2, 5.875%, 6/1/47                                2,403,125


The accompanying notes are an integral part of these financial statements.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 19


Schedule of Investments | 4/30/17 (continued)



-----------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                    Value
-----------------------------------------------------------------------------------------------------------
                                                                                     
                          Ohio -- (continued)
    1,700,000             Buckeye Tobacco Settlement Financing Authority,
                          Asset-Backed, Series A-2, 6.0%, 6/1/42                           $      1,660,696
    6,000,000             Buckeye Tobacco Settlement Financing Authority,
                          Asset-Backed, Series A-2, 6.5%, 6/1/47                                  6,016,320
    3,000,000(d)          Ohio Air Quality Development Authority, FirstEnergy
                          Solutions Corp. Project, Series D, 4.25%, 8/1/29                        2,790,030
    2,500,000(e)          State of Ohio, Common Schools, Series B, 5.0%, 6/15/29                  2,897,850
                                                                                           ----------------
                                                                                           $     17,032,111
-----------------------------------------------------------------------------------------------------------
                          Oregon -- 2.4%
    1,000,000             Oregon Health & Science University, Series A,
                          5.0%, 7/1/42                                                     $      1,137,530
    5,190,000             Oregon Health & Science University, Series E,
                          5.0%, 7/1/32                                                            5,794,635
                                                                                           ----------------
                                                                                           $      6,932,165
-----------------------------------------------------------------------------------------------------------
                          Pennsylvania -- 6.5%
    1,550,000             Allegheny County Hospital Development Authority, South
                          Hills Health, Series A, 5.125%, 5/1/25                           $      1,552,154
    1,280,000(c)          Langhorne Manor Borough Higher Education Authority,
                          Lower Bucks Hospital, 7.35%, 7/1/22                                       313,664
    5,000,000             Pennsylvania Economic Development Financing Authority,
                          USG Corp. Project, 6.0%, 6/1/31                                         4,980,850
      500,000             Philadelphia Authority for Industrial Development, Greater
                          Philadelphia Health Action, Inc., Project, Series A,
                          6.625%, 6/1/50                                                            514,605
    2,000,000             Philadelphia Authority for Industrial Development, Nueva
                          Esperanze, Inc., 8.2%, 12/1/43                                          2,277,680
    1,000,000             Philadelphia Authority for Industrial Development,
                          Performing Arts Charter School Project, 6.5%,
                          6/15/33 (144A)                                                          1,047,910
    2,000,000             Philadelphia Authority for Industrial Development,
                          Performing Arts Charter School Project, 6.75%,
                          6/15/43 (144A)                                                          2,103,960
    5,900,000             Philadelphia Hospitals & Higher Education Facilities
                          Authority, Temple University Health System, Series A,
                          5.0%, 7/1/34                                                            5,910,797
                                                                                           ----------------
                                                                                           $     18,701,620
-----------------------------------------------------------------------------------------------------------
                          Puerto Rico -- 1.4%
    6,255,000(c)(e)       Commonwealth of Puerto Rico, Series A, 8.0%, 7/1/35              $      3,971,925
-----------------------------------------------------------------------------------------------------------
                          Rhode Island -- 1.5%
    5,900,000(c)          Central Falls Detention Facility Corp., 7.25%, 7/15/35           $      1,459,365
    1,500,000(f)          Rhode Island Health & Educational Building Corp.,
                          Tockwatten Home Issue, 8.375%, 1/1/46                                   1,859,430
   10,000,000(b)          Tobacco Settlement Financing Corp., Asset-Backed,
                          Series A, 6/1/52                                                          996,800
                                                                                           ----------------
                                                                                           $      4,315,595
-----------------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

20 Pioneer Municipal High Income Trust | Annual Report | 4/30/17




-----------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                    Value
-----------------------------------------------------------------------------------------------------------
                                                                                     
                          Texas -- 14.8%
    1,000,000             Arlington Higher Education Finance Corp., Universal
                          Academy, Series A, 7.0%, 3/1/34                                  $      1,005,250
    2,500,000(f)          Central Texas Regional Mobility Authority, Sub Lien,
                          6.75%, 1/1/41                                                           2,978,400
    2,490,000(e)          County of Harris, TX, Series A, 5.0%, 10/1/26                           3,021,864
    5,000,000(e)          Goose Creek Consolidated Independent School District,
                          Series C, 4.0%, 2/15/26 (PSF-GTD Insured)                               5,625,350
      725,078(c)          Gulf Coast Industrial Development Authority, Microgy
                          Holdings Project, 7.0%, 12/1/36                                                 7
    3,545,000(d)          Harris County Health Facilities Development Corp.,
                          The Methodist Hospital System, Series A-2,
                          0.87%, 12/1/41                                                          3,545,000
      735,000(d)          Lower Neches Valley Authority Industrial Development
                          Corp., Exxon Capital Ventures, Inc., 0.85%, 11/1/38                       735,000
    3,785,000             North Texas Tollway Authority, Series A, 5.0%, 1/1/35                   4,239,768
   10,000,000(f)          North Texas Tollway Authority, Series F, 5.75%, 1/1/33                 10,325,500
    1,500,000(f)          Red River Health Facilities Development Corp., MRC
                          Crestview, Series A, 8.0%, 11/15/41                                     1,919,595
    3,960,000(h)          Sanger Industrial Development Corp., Texas Pellets Project,
                          Series B, 8.0%, 7/1/38                                                  2,376,000
    1,000,000             Tarrant County Cultural Education Facilities Finance Corp.,
                          Mirador Project, Series A, 8.125%, 11/15/39                               900,000
    1,000,000             Tarrant County Cultural Education Facilities Finance Corp.,
                          Mirador Project, Series A, 8.25%, 11/15/44                                900,000
    2,000,000(f)          Tarrant County Cultural Education Facilities Finance Corp.,
                          MRC Crestview Project, 8.0%, 11/15/34                                   2,453,860
    2,500,000             Travis County Health Facilities Development Corp., Longhorn
                          Village Project, 7.125%, 1/1/46                                         2,713,175
                                                                                           ----------------
                                                                                           $     42,738,769
-----------------------------------------------------------------------------------------------------------
                          Utah -- 0.4%
    1,000,000             Salt Lake City Corp., Airport Revenue, Series B,
                          5.0%, 7/1/35                                                     $      1,159,000
-----------------------------------------------------------------------------------------------------------
                          Virginia -- 2.0%
    1,415,000(e)          County of Fairfax, VA, Series A, 4.0%, 10/1/33 (ST AID
                          WITHHLDG Insured)                                                $      1,535,657
    4,000,000             Upper Occoquan Sewage Authority, 4.0%, 7/1/41                           4,187,360
                                                                                           ----------------
                                                                                           $      5,723,017
-----------------------------------------------------------------------------------------------------------
                          Washington -- 9.7%
    3,745,000             City of Seattle, WA, Water System Revenue, 4.0%, 8/1/32          $      4,033,365
    2,500,000(e)          King County Issaquah School District No. 411, 4.0%,
                          12/1/31 (SCH BD GTY Insured)                                            2,705,875
   14,315,000(b)(e)       State of Washington, Motor Vehicle Sales Tax, Series C,
                          6/1/22 (NATL Insured)                                                  13,067,305
    2,500,000             University of Washington, Series B, 5.0%, 6/1/29                        2,949,400


The accompanying notes are an integral part of these financial statements.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 21


Schedule of Investments | 4/30/17 (continued)



------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                    Value
------------------------------------------------------------------------------------------------------------
                                                                                     
                          Washington -- (continued)
    3,795,000(f)          Washington State Health Care Facilities Authority, Fred
                          Hutchinson Cancer Research Center, Series A,
                          6.0%, 1/1/33                                                     $      4,180,534
    1,150,000             Washington State Housing Finance Commission, Mirabella
                          Project, Series A, 6.75%, 10/1/47 (144A)                                1,195,022
                                                                                           -----------------
                                                                                           $     28,131,501
------------------------------------------------------------------------------------------------------------
                          West Virginia -- 0.6%
    2,000,000(c)          City of Philippi, WV, Alderson-Broaddus College, Inc.,
                          Series A, 7.75%, 10/1/44                                         $      1,200,000
      725,000(c)          West Virginia Hospital Finance Authority, Highland Hospital
                          Group, 9.125%, 10/1/41                                                    670,263
                                                                                           -----------------
                                                                                           $      1,870,263
------------------------------------------------------------------------------------------------------------
                          Wisconsin -- 4.9%
    5,000,000             Public Finance Authority, Glenridge Palmer Ranch, Series A,
                          8.25%, 6/1/46                                                    $      5,926,950
      750,000             Public Finance Authority, Roseman University Health
                          Sciences Project, 5.875%, 4/1/45                                          769,283
    1,500,000             Public Finance Authority, SearStone CCRC Project, Series A,
                          8.625%, 6/1/47 (144A)                                                   1,704,735
    5,000,000             Wisconsin Department of Transportation, Series A,
                          5.0%, 7/1/28                                                            5,889,900
                                                                                           -----------------
                                                                                           $     14,290,868
------------------------------------------------------------------------------------------------------------
                          TOTAL TAX EXEMPT OBLIGATIONS
                          (Cost $371,594,885)                                              $    385,315,194
------------------------------------------------------------------------------------------------------------
                          MUNICIPAL COLLATERALIZED DEBT OBLIGATION --
                          0.1% of Net Assets
   10,000,000(d)          Non-Profit Preferred Funding Trust I, Series E, 0.0%,
                          9/15/37 (144A)                                                   $        200,000
------------------------------------------------------------------------------------------------------------
                          TOTAL MUNICIPAL COLLATERALIZED DEBT OBLIGATION
                          (Cost $10,000,000)                                               $        200,000
------------------------------------------------------------------------------------------------------------
                          TOTAL INVESTMENTS IN SECURITIES -- 133.1%
                          (Cost -- $381,594,885) (i)                                       $    385,515,194
------------------------------------------------------------------------------------------------------------
                          OTHER ASSETS AND LIABILITIES -- 1.8%                             $      5,247,608
------------------------------------------------------------------------------------------------------------
                          PREFERRED SHARES AT REDEMPTION VALUE,
                          INCLUDING DIVIDENDS PAYABLE -- (34.9)%                           $   (101,022,229)
------------------------------------------------------------------------------------------------------------
                          NET ASSETS APPLICABLE TO
                          COMMON SHAREOWNERS -- 100.0%                                     $    289,740,573
============================================================================================================


The accompanying notes are an integral part of these financial statements.

22 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


(144A)     Security is exempt from registration under Rule 144A of the
           Securities Act of 1933. Such securities may be resold normally to
           qualified institutional buyers in a transaction exempt from
           registration. At April 30, 2017, the value of these securities
           amounted to $27,785,778, or 9.6% of net assets applicable to common
           shareowners.

RIB        Residual Interest Bond is purchased in a secondary market. The
           interest rate is subject to change periodically and inversely based
           upon prevailing market rates. The interest rate shown is the rate at
           April 30, 2017.

+          Amount rounds to less than 0.1%.

(a)        Consists of Revenue Bonds unless otherwise indicated.

(b)        Security issued with a zero coupon. Income is recognized through
           accretion of discount.

(c)        Security is in default.

(d)        The interest rate is subject to change periodically. The interest
           rate shown is the rate at April 30, 2017.

(e)        Represents a General Obligation Bond.

(f)        Prerefunded bonds have been collateralized by U.S. Treasury or U.S.
           Government Agency securities which are held in escrow to pay interest
           and principal on the tax exempt issue and to retire the bonds in full
           at the earliest refunding date.

(g)        Escrow to maturity.

(h)        Security is valued using fair value methods (other than prices
           supplied by independent pricing services). See Notes to Financial
           Statements -- Note 1A.

(i)        At April 30, 2017, the net unrealized appreciation on investments
           based on cost for federal tax purposes of $374,344,088 was as
           follows:



                                                                            
            Aggregate gross unrealized appreciation for all investments
              in which there is an excess of value over tax cost               $  41,977,057

            Aggregate gross unrealized depreciation for all investments
              in which there is an excess of tax cost over value                 (30,805,951)
                                                                               -------------
            Net unrealized appreciation                                        $  11,171,106
                                                                               =============


Purchases and sales of securities (excluding temporary cash investments) for the
year ended April 30, 2017 aggregated $89,075,262 and $75,032,519 respectively.

The Trust is permitted to engage in purchase and sale transactions ("cross
trades") with certain funds and accounts for which Pioneer Investment
Management, Inc. (PIM) serves as the investment adviser, as set forth in Rule
17a-7 under the Investment Company Act of 1940, pursuant to procedures adopted
by the Board of Trustees. Under these procedures, cross trades are effected at
current market prices. During the year ended April 30, 2017, the Trust did not
engage in cross trade activity.

Various inputs are used in determining the value of the Trust's investments.
These inputs are summarized in the three broad levels below.

    Level 1 - quoted prices in active markets for identical securities.

    Level 2 - other significant observable inputs (including quoted prices for
              similar securities, interest rates, prepayment speeds, credit
              risks, etc.). See Notes to Financial Statements -- Note 1A.

    Level 3 - significant unobservable inputs (including the Trust's own
              assumptions in determining fair value of investments). See Notes
              to Financial Statements -- Note 1A.

The accompanying notes are an integral part of these financial statements.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 23


Schedule of Investments | 4/30/17 (continued)

The following is a summary of the inputs used as of April 30, 2017, in valuing
the Trust's investments.



------------------------------------------------------------------------------------
                                     Level 1  Level 2       Level 3     Total
------------------------------------------------------------------------------------
                                                            
Tax Exempt Obligations
   Texas                             $ --     $ 40,362,769  $2,376,000  $ 42,738,769
   All Other Tax Exempt Obligations    --      342,576,425          --   342,576,425
Municipal Collateralized
   Debt Obligation                     --          200,000          --       200,000
------------------------------------------------------------------------------------
Total                                $ --     $383,139,194  $2,376,000  $385,515,194
====================================================================================



The following is a reconciliation of assets valued using significant
unobservable inputs (Level 3):



--------------------------------------------------------------------------------
                                                         Tax Exempt Obligations
--------------------------------------------------------------------------------
                                                                
Balance as of 4/30/16                                              $         --
Realized gain (loss)(1)                                                      --
Change in unrealized appreciation (depreciation)(2)                  (1,134,359)
Purchases                                                                    --
Sales                                                                        --
Accrued discounts/premiums                                               (4,299)
Transfer in and out of Level 3*                                       3,514,658
--------------------------------------------------------------------------------
Total                                                              $  2,376,000
================================================================================



(1)  Realized gain (loss) on these securities is included in the net realized
     gain (loss) from investments in the Statement of Operations.

(2)  Unrealized appreciation (depreciation) on these securities is included in
     the change in unrealized appreciation (depreciation) on investments in the
     Statement of Operations.

*    Transfers are calculated on the beginning of period value. For the year
     ended April 30, 2017, there were no transfers between Levels 1 and 2 or
     between Levels 1 and 3. A security with an aggregate market value of
     $3,514,658 transferred from Level 2 to Level 3 as there were no longer
     observable inputs available to determine its value.



                                                                              
Net change in unrealized appreciation (depreciation) of investments still held
as of 4/30/17                                                                    $(1,134,359)
                                                                                 -----------


The accompanying notes are an integral part of these financial statements.

24 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Statement of Assets and Liabilities | 4/30/17



                                                                          
ASSETS:
  Investments in securities, at value (cost $381,594,885)                    $385,515,194
  Receivables --
     Interest                                                                   6,006,295
     Investment securities sold                                                   535,000
  Prepaid expenses                                                                     92
------------------------------------------------------------------------------------------
        Total assets                                                         $392,056,581
==========================================================================================
LIABILITIES:
  Due to custodian                                                           $    961,149
  Payables --
     Administration fee                                                            98,996
     Trustees' fees                                                                 1,942
  Due to affiliates                                                               192,009
  Accrued expenses                                                                 39,683
------------------------------------------------------------------------------------------
        Total liabilities                                                    $  1,293,779
==========================================================================================
PREFERRED SHARES AT REDEMPTION VALUE:
  $25,000 liquidation value per share applicable to 4,040 shares, including
     dividends payable of $22,229                                            $101,022,229
------------------------------------------------------------------------------------------
NET ASSETS APPLICABLE TO COMMON SHAREOWNERS:
  Paid-in capital                                                            $309,976,185
  Undistributed net investment income                                           3,465,527
  Accumulated net realized loss on investments                                (27,621,448)
  Net unrealized appreciation on investments                                    3,920,309
------------------------------------------------------------------------------------------
        Net assets applicable to common shareowners                          $289,740,573
==========================================================================================
NET ASSET VALUE PER COMMON SHARE:
  No par value (unlimited number of shares authorized)
     Based on $289,740,573 / 22,771,349 common shares                        $      12.72
==========================================================================================


The accompanying notes are an integral part of these financial statements.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 25


Statement of Operations

For the Year Ended 4/30/17



                                                                                 
INVESTMENT INCOME:
  Interest                                                           $ 19,560,960
----------------------------------------------------------------------------------------------------
     Total investment income                                                           $ 19,560,960
----------------------------------------------------------------------------------------------------
EXPENSES:
  Management fees                                                    $  2,400,087
  Administrative expense                                                  215,139
  Transfer agent fees                                                      17,281
  Shareholder communications expense                                       20,206
  Auction agent fees                                                      103,235
  Custodian fees                                                            6,440
  Professional fees                                                        94,151
  Printing expense                                                          7,232
  Trustees' fees                                                           15,724
  Pricing fees                                                             19,483
  Miscellaneous                                                            98,148
----------------------------------------------------------------------------------------------------
     Total expenses                                                                    $  2,997,126
----------------------------------------------------------------------------------------------------
         Net investment income                                                         $ 16,563,834
----------------------------------------------------------------------------------------------------
REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS:
  Net realized gain (loss) on investments:                          $    (654,552)
  Change in net unrealized appreciation (depreciation)
     on investments:                                                  (16,590,447)
----------------------------------------------------------------------------------------------------
        Net realized and unrealized gain (loss) on investments                         $(17,244,999)
----------------------------------------------------------------------------------------------------
DISTRIBUTIONS TO PREFERRED SHAREOWNERS FROM
NET INVESTMENT INCOME:                                                                 $ (1,150,946)
----------------------------------------------------------------------------------------------------
  Net decrease in net assets resulting from operations                                 $ (1,832,111)
====================================================================================================


The accompanying notes are an integral part of these financial statements.

26 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Statements of Changes in Net Assets



-----------------------------------------------------------------------------------------
                                                           Year Ended      Year Ended
                                                           4/30/17         4/30/16
-----------------------------------------------------------------------------------------
                                                                     
FROM OPERATIONS:
Net investment income (loss)                               $  16,563,834   $  18,820,592
Net realized gain (loss) on investments                         (654,552)        150,831
Change in net unrealized appreciation (depreciation)
   on investments                                            (16,590,447)      4,498,035
Distributions to preferred shareowners from net
   investment income                                          (1,150,946)       (301,213)
-----------------------------------------------------------------------------------------
      Net increase (decrease) in net assets resulting
         from operations                                   $  (1,832,111)  $  23,168,245
-----------------------------------------------------------------------------------------
DISTRIBUTIONS TO COMMON SHAREOWNERS:
Net investment income and previously undistributed
   net investment income ($0.69 and $0.84 per
   share, respectively)                                    $ (15,653,258)  $ (19,102,844)
-----------------------------------------------------------------------------------------
         Total distributions to common shareowners         $ (15,653,258)  $ (19,102,844)
-----------------------------------------------------------------------------------------
FROM TRUST SHARE TRANSACTIONS:
Reinvestment of distributions                              $     199,322   $     243,355
-----------------------------------------------------------------------------------------
      Net increase in net assets applicable to common
         shareowners from Trust share transactions         $     199,322   $     243,355
-----------------------------------------------------------------------------------------
      Net increase (decrease) in net assets applicable to
         common shareowners                                $ (17,286,047)  $   4,308,756
NET ASSETS APPLICABLE TO COMMON SHAREOWNERS:
Beginning of year                                          $ 307,026,620   $ 302,717,864
-----------------------------------------------------------------------------------------
End of year                                                $ 289,740,573   $ 307,026,620
-----------------------------------------------------------------------------------------
Undistributed net investment income                        $   3,465,527   $   3,227,519
=========================================================================================


The accompanying notes are an integral part of these financial statements.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 27


Financial Highlights



------------------------------------------------------------------------------------------------------------------------------
                                                                     Year        Year        Year        Year        Year
                                                                     Ended       Ended       Ended       Ended       Ended
                                                                     4/30/17     4/30/16     4/30/15     4/30/14     4/30/13
------------------------------------------------------------------------------------------------------------------------------
                                                                                                      
Per Share Operating Performance
Net asset value, beginning of period                                 $  13.49    $  13.31    $  13.33    $  14.72    $  14.12
------------------------------------------------------------------------------------------------------------------------------
Increase (decrease) from investment operations: (a)
   Net investment income                                             $   0.73    $   0.83    $   0.91    $   1.05    $   1.14
   Net realized and unrealized gain (loss) on investments               (0.76)       0.20        0.16       (1.29)       0.61
------------------------------------------------------------------------------------------------------------------------------
Distributions to preferred shareowners from:
   Net investment income                                             $  (0.05)   $  (0.01)   $  (0.01)   $  (0.01)   $  (0.01)
------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) from investment operations                   $  (0.08)   $   1.02    $   1.06    $  (0.25)   $   1.74
------------------------------------------------------------------------------------------------------------------------------
Distributions to common shareowners from:
   Net investment income and previously undistributed
      net investment income                                          $  (0.69)   $  (0.84)*  $  (1.08)*  $  (1.14)*  $  (1.14)
------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) in net asset value                           $  (0.77)   $   0.18    $  (0.02)   $  (1.39)   $   0.60
------------------------------------------------------------------------------------------------------------------------------
Net asset value, end of period                                       $  12.72    $  13.49    $  13.31    $  13.33    $  14.72
------------------------------------------------------------------------------------------------------------------------------
Market value, end of period                                          $  11.75    $  14.07    $  14.75    $  14.90    $  16.02
==============================================================================================================================
Total return at net asset value (b)                                     (0.45)%      8.12%       7.76%      (1.57)%     12.45%
Total return at market value (b)                                       (11.83)%      1.75%       6.84%       1.10%      11.48%
Ratios to average net assets of common shareowners:
   Total expenses (c)                                                    1.00%       1.05%       1.03%       1.04%       1.03%
   Net investment income before preferred share distributions            5.54%       6.24%       6.73%       7.89%       7.84%
   Preferred share distributions                                         0.38%       0.10%       0.04%       0.05%       0.08%
   Net investment income available to common shareowners                 5.16%       6.14%       6.69%       7.84%       7.76%
Portfolio turnover                                                         19%          9%         14%         19%         10%
Net assets of common shareowners, end of period (in thousands)       $289,741    $307,027    $302,718    $301,872    $332,193


The accompanying notes are an integral part of these financial statements.

28 Pioneer Municipal High Income Trust | Annual Report | 4/30/17




------------------------------------------------------------------------------------------------------------------------------
                                                                     Year        Year        Year        Year        Year
                                                                     Ended       Ended       Ended       Ended       Ended
                                                                     4/30/17     4/30/16     4/30/15     4/30/14     4/30/13
------------------------------------------------------------------------------------------------------------------------------
                                                                                                      
Preferred shares outstanding (in thousands)                          $101,000    $101,000    $101,000    $101,000    $101,000
Asset coverage per preferred share, end of period                    $ 96,723    $100,998    $ 99,930    $ 99,721    $107,211
Average market value per preferred share (d)                         $ 25,000    $ 25,000    $ 25,000    $ 25,000    $ 25,000
Liquidation value, including dividends payable, per preferred share  $ 25,006    $ 25,001    $ 25,000    $ 25,001    $ 25,001
------------------------------------------------------------------------------------------------------------------------------


*    The amount of distributions made to shareowners during the year were in
     excess of the net investment income earned by the Trust during the year.
     The Trust has accumulated undistributed net investment income which is part
     of the Trust's NAV. A portion of the accumulated net investment income was
     distributed to shareowners during the year.

(a)  The per common share data presented above is based upon the average common
     shares outstanding for the periods presented.

(b)  Total investment return is calculated assuming a purchase of common shares
     at the current net asset value or market value on the first day and a sale
     at the current net asset value or market value on the last day of the
     periods reported. Dividends and distributions, if any, are assumed for
     purposes of this calculation to be reinvested at prices obtained under the
     Trust's dividend reinvestment plan. Total investment return does not
     reflect brokerage commissions. Past performance is not a guarantee of
     future results.

(c)  Expense ratios do not reflect the effect of distribution payments to
     preferred shareowners.

(d)  Market value is redemption value without an active market.

The accompanying notes are an integral part of these financial statements.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 29


Notes to Financial Statements | 4/30/17

1. Organization and Significant Accounting Policies

Pioneer Municipal High Income Trust (the Trust) was organized as a Delaware
statutory trust on March 13, 2003. Prior to commencing operations on July 21,
2003, the Trust had no operations other than matters relating to its
organization and registration as a diversified, closed-end management investment
company under the Investment Company Act of 1940, as amended. The investment
objective of the Trust is to seek a high level of current income exempt from
regular federal income tax, and the Trust may, as a secondary objective, also
seek capital appreciation to the extent that it is consistent with its primary
investment objective.

The Trust's financial statements have been prepared in conformity with U.S.
generally accepted accounting principles (U.S. GAAP) that require the management
of the Trust to make estimates and assumptions that affect the reported amounts
of assets and liabilities, the disclosure of contingent assets and liabilities
at the date of the financial statements, and the reported amounts of income,
expenses and gain or loss on investments during the reporting period. Actual
results could differ from those estimates.

The Trust is an investment company and follows investment company accounting and
reporting guidance under U.S. GAAP. The following is a summary of significant
accounting policies followed by the Trust in the preparation of its financial
statements:

A.   Security Valuation

     The net asset value of the Trust is computed once daily, on each day the
     New York Stock Exchange (NYSE) is open, as of the close of regular trading
     on the NYSE.

     Fixed-income securities are valued by using prices supplied by independent
     pricing services, which consider such factors as market prices, market
     events, quotations from one or more brokers, Treasury spreads, yields,
     maturities and ratings, or may use a pricing matrix or other fair value
     methods or techniques to provide an estimated value of the security or
     instrument. A pricing matrix is a means of valuing a debt security on the
     basis of current market prices for other debt securities, historical
     trading patterns in the market for fixed-income securities and/or other
     factors. Non-U.S. debt securities that are listed on an exchange will be
     valued at the bid price obtained from an independent third party pricing
     service. When independent third party pricing services are unable to supply
     prices, or when prices or market quotations are considered to be
     unreliable, the value of that security may be determined using quotations
     from one or more broker-dealers.

30 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


     Shares of open-end registered investment companies (including money market
     mutual funds) are valued at such funds' net asset value. Repurchase
     agreements are valued at par. Cash may include overnight time deposits at
     approved financial institutions.

     Securities for which independent pricing services or broker-dealers are
     unable to supply prices or for which market prices and/or quotations are
     not readily available or are considered to be unreliable are valued by a
     fair valuation team comprised of certain personnel of Pioneer Investment
     Management, Inc. (PIM), the Trust's investment adviser and wholly owned
     indirect subsidiary of UniCredit S.p.A. (UniCredit), pursuant to procedures
     adopted by the Trust's Board of Trustees. PIM's fair valuation team uses
     fair value methods approved by the Valuation Committee of the Board of
     Trustees. PIM's fair valuation team is responsible for monitoring
     developments that may impact fair valued securities and for discussing and
     assessing fair values on an ongoing basis, and at least quarterly, with the
     Valuation Committee of the Board of Trustees.

     Inputs used when applying fair value methods to value a security may
     include credit ratings, the financial condition of the company, current
     market conditions and comparable securities. The Trust may use fair value
     methods if it is determined that a significant event has occurred after the
     close of the exchange or market on which the security trades and prior to
     the determination of the Trust's net asset value. Examples of a significant
     event might include political or economic news, corporate restructurings,
     natural disasters, terrorist activity or trading halts. Thus, the valuation
     of the Trust's securities may differ significantly from exchange prices and
     such differences could be material.

     At April 30, 2017, one security was valued using fair value methods (in
     addition to securities valued using prices supplied by independent pricing
     services) representing 0.8% of net assets. The value of this fair valued
     security is $2,376,000.

B.   Investment Income and Transactions

     Interest income, including interest on income-bearing cash accounts, is
     recorded on an accrual basis, net of unrecoverable foreign taxes withheld
     at the applicable country rates.

     Discounts and premiums on purchase prices of debt securities are accreted
     or amortized, respectively, daily, into interest income on an effective
     yield to maturity basis with a corresponding increase or decrease in the
     cost basis of the security. Premiums and discounts related to certain
     mortgage-backed securities are amortized or accreted in proportion to the
     monthly paydowns.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 31


     Security transactions are recorded as of trade date. Gains and losses on
     sales of investments are calculated on the identified cost method for both
     financial reporting and federal income tax purposes.

C.   Federal Income Taxes

     It is the Trust's policy to comply with the requirements of the Internal
     Revenue Code applicable to regulated investment companies and to distribute
     all of its net taxable income and net realized capital gains, if any, to
     its shareowners. Therefore, no federal income tax provision is required. As
     of April 30, 2017, the Trust did not accrue any interest or penalties with
     respect to uncertain tax positions, which if applicable, would be recorded
     as an income tax expense in the Statement of Operations. Tax returns filed
     within the prior three years remain subject to examination by federal and
     state tax authorities.

     The amount and character of income and capital gain distributions to
     shareowners are determined in accordance with federal income tax rules,
     which may differ from U.S. GAAP. Distributions in excess of net investment
     income or net realized gains are temporary overdistributions for financial
     statement and tax purposes. Capital accounts within the financial
     statements are adjusted for permanent book/tax differences to reflect tax
     character, but are not adjusted for temporary differences.

     At April 30, 2017, the Trust reclassified $4,586,154 to decrease paid-in
     capital, $478,378 to increase undistributed net investment income and
     $4,107,776 to decrease accumulated net realized loss on investments to
     reflect permanent book/tax differences. These adjustments have no impact on
     the net assets or results of operations.

     At April 30, 2017, the Trust was permitted to carry forward $20,936,841 of
     long-term capital losses without limitation. Additionally, at April 30,
     2017, the Trust had a net capital loss carry forward of $8,980,139 which
     will expire in 2018 if not utilized. Since unlimited losses are required to
     be used first, loss carry forwards that are subject to expiration may be
     more likely to expire unused.

     The Trust has elected to defer $1,416,738 of short-term capital losses and
     and $1,653,980 of long-term capital losses recognized between November 1,
     2016 and April 30, 2017, to its fiscal year ending April 30, 2018.

     The tax character of distributions paid to shareowners during the years
     ended April 30, 2017 and April 30, 2016 were as follows:

32 Pioneer Municipal High Income Trust | Annual Report | 4/30/17




     ---------------------------------------------------------------------------
                                                              2017          2016
     ---------------------------------------------------------------------------
                                                               
     Distributions paid from:
     Tax exempt income                                 $16,732,954   $18,873,304
     Ordinary income                                        71,250       530,753
     ---------------------------------------------------------------------------
          Total                                        $16,804,204   $19,404,057
     ===========================================================================


     The following shows the components of distributable earnings (losses) on a
     federal income tax basis at April 30, 2017:



     ---------------------------------------------------------------------------
                                                                           2017
     ---------------------------------------------------------------------------
                                                                
     Distributable earnings:
     Undistributed ordinary income                                 $    413,602
     Capital loss carryforward                                      (29,916,980)
     Late year loss deferrals                                        (3,070,718)
     Other book/tax temporary differences                             7,250,771
     Tax-exempt spillback                                             1,167,404
     Unrealized appreciation                                          3,920,309
     ---------------------------------------------------------------------------
          Total                                                    $(20,235,612)
     ===========================================================================


     The difference between book-basis and tax-basis unrealized appreciation/
     depreciation is primarily attributable to the realization for tax purposes
     of unrealized gains on investments in passive foreign investment companies,
     the book/tax differences in the accrual of income on securities in default,
     the difference between book and tax amortization methods and discounts on
     fixed income securities.

D.   Automatic Dividend Reinvestment Plan

     All shareowners whose shares are registered in their own names
     automatically participate in the Automatic Dividend Reinvestment Plan (the
     Plan), under which participants receive all dividends and capital gain
     distributions (collectively, dividends) in full and fractional shares of
     the Trust in lieu of cash. Shareowners may elect not to participate in the
     Plan. Shareowners not participating in the Plan receive all dividends and
     capital gain distributions in cash. Participation in the Plan is completely
     voluntary and may be terminated or resumed at any time without penalty by
     notifying American Stock Transfer & Trust Company, the agent for
     shareowners in administering the Plan (the Plan Agent), in writing prior to
     any dividend record date; otherwise such termination or resumption will be
     effective with respect to any subsequently declared dividend or other
     distribution.

     If a shareowner's shares are held in the name of a brokerage firm, bank or
     other nominee, the shareowner can ask the firm or nominee to participate in
     the Plan on the shareowner's behalf. If the firm or nominee does not offer
     the

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 33


     Plan, dividends will be paid in cash to the shareowner of record. A firm or
     nominee may reinvest a shareowner's cash dividends in shares of the Trust
     on terms that differ from the terms of the Plan.

     Whenever the Trust declares a dividend on shares payable in cash,
     participants in the Plan will receive the equivalent in shares acquired by
     the Plan Agent either (i) through receipt of additional unissued but
     authorized shares from the Trust or (ii) by purchase of outstanding shares
     on the New York Stock Exchange or elsewhere. If, on the payment date for
     any dividend, the net asset value per share is equal to or less than the
     market price per share plus estimated brokerage trading fees (market
     premium), the Plan Agent will invest the dividend amount in newly issued
     shares. The number of newly issued shares to be credited to each account
     will be determined by dividing the dollar amount of the dividend by the net
     asset value per share on the date the shares are issued, provided that the
     maximum discount from the then current market price per share on the date
     of issuance does not exceed 5%. If, on the payment date for any dividend,
     the net asset value per share is greater than the market value (market
     discount), the Plan Agent will invest the dividend amount in shares
     acquired in open-market purchases. There are no brokerage charges with
     respect to newly issued shares. However, each participant will pay a pro
     rata share of brokerage trading fees incurred with respect to the Plan
     Agent's open-market purchases. Participating in the Plan does not relieve
     shareowners from any federal, state or local taxes which may be due on
     dividends paid in any taxable year. Shareowners holding Plan shares in a
     brokerage account may be able to transfer the shares to another broker and
     continue to participate in the Plan.

E.   Risks

     The value of securities held by the Trust may go up or down, sometimes
     rapidly or unpredictably, due to general market conditions, such as real or
     perceived adverse economic, political or regulatory conditions, inflation,
     changes in interest rates, lack of liquidity in the bond markets or adverse
     investor sentiment. In the past several years, financial markets have
     experienced increased volatility, depressed valuations, decreased liquidity
     and heightened uncertainty. These conditions may continue, recur, worsen or
     spread.

     Interest rates in the U.S. recently have been historically low, so the
     Trust faces a heightened risk that interest rates may rise. A general rise
     in interest rates may cause investors to move out of fixed income
     securities on a large scale, which could adversely affect the price and
     liquidity of fixed income securities.

     The municipal bond market can be susceptible to unusual volatility,
     particularly for lower-rated and unrated securities. Liquidity can be
     reduced unpredictably in response to overall economic conditions or credit

34 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


     tightening. Municipal issuers may be adversely affected by rising health
     care costs, increasing unfunded pension liabilities, and by the phasing out
     of federal programs providing financial support. Unfavorable conditions and
     developments relating to projects financed with municipal securities can
     result in lower revenues to issuers of municipal securities, potentially
     resulting in defaults. Issuers often depend on revenues from these projects
     to make principal and interest payments. The value of municipal securities
     can also be adversely affected by changes in the financial condition of one
     or more individual municipal issuers or insurers of municipal issuers,
     regulatory and political developments, tax law changes or other legislative
     actions, and by uncertainties and public perceptions concerning these and
     other factors. Municipal securities may be more susceptible to down-grades
     or defaults during recessions or similar periods of economic stress. In
     recent periods, an increasing number of municipal issuers in the United
     States have defaulted on obligations and commenced insolvency proceedings.
     Financial difficulties of municipal issuers may continue or get worse. To
     the extent the Trust invests significantly in a single state, including
     California, Illinois and Texas, or in securities the payments on which are
     dependent upon a single project or source of revenues, or that relate to a
     sector or industry, including health care facilities, education,
     transportation, special revenues and pollution control, the Trust will be
     more susceptible to associated risks and developments.

2. Management Agreement

PIM manages the Trust's portfolio. Management fees payable under the Trust's
Advisory Agreement with PIM are calculated daily at the annual rate of 0.60% of
the Trust's average daily managed assets. "Managed assets" means (a) the total
assets of the Trust, including any form of investment leverage, minus (b) all
accrued liabilities incurred in the normal course of operations, which shall not
include any liabilities or obligations attributable to investment leverage
obtained through (i) indebtedness of any type (including, without limitation,
borrowing through a credit facility or the issuance of debt securities), (ii)
the issuance of preferred stock or other similar preference securities, and/or
(iii) any other means. For the year ended April 30, 2017, the net management fee
was 0.60% of the Trust's average daily managed assets, which was equivalent to
0.80% of the Trust's average daily net assets.

In addition, under PIM's management and administration agreements, certain other
services and costs are paid by PIM and reimbursed by the Trust. At April 30,
2017, $291,005 was payable to PIM related to management costs, administrative
costs and certain other services is included in "Due to affiliates" and
"Administration fee" on the Statement of Assets and Liabilities.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 35


3. Transfer Agent

American Stock Transfer & Trust Company (AST) serves as the transfer agent with
respect to the Trust's common shares. The Trust pays AST an annual fee, as is
agreed to from time to time by the Trust and AST, for providing such services.

In addition, the Trust reimbursed the transfer agent for out-of-pocket expenses
incurred by the transfer agent related to shareowner communications activities
such as proxy and statement mailings and outgoing calls.

Deutsche Bank Trust Company Americas (Deutsche Bank) is the transfer agent,
registrar, dividend-paying agent and auction agent with respect to the Trust's
auction preferred shares (APS). The Trust pays Deutsche Bank an annual fee, as
is agreed to from time to time by the Trust and Deutsche Bank, for providing
such services.

4. Trust Shares

There are an unlimited number of common shares of beneficial interest
authorized.

Transactions in common shares of beneficial interest for the year ended April
30, 2017 and the year ended April 30, 2016 were as follows:



--------------------------------------------------------------------------------
                                                         4/30/17        4/30/16
--------------------------------------------------------------------------------
                                                                
Shares outstanding at beginning of year                22,756,724     22,738,580
Reinvestment of distributions                              14,625         18,144
--------------------------------------------------------------------------------
Shares outstanding at end of year                      22,771,349     22,756,724
================================================================================


The Trust may classify or reclassify any unissued shares of beneficial interest
into one or more series of preferred shares of beneficial interest. As of April
30, 2017, there were 4,040 APS as follows: Series A -- 2,000 and Series B --
2,040.

Dividends on Series A and Series B are cumulative at a rate which is to be reset
every seven days based on the results of an auction. An auction fails if there
are more APS offered for sale than there are buyers. When an auction fails, the
dividend rate for the period will be the maximum rate on the auction dates
described in the prospectus for the APS. Preferred shareowners are not able to
sell their APS at an auction if the auction fails. Since February 2008, the
Trust's auctions related to the APS have failed. The maximum rate for each
series is 125% of the 7 day commercial paper rate or adjusted Kenny rate.
Dividend rates on APS ranged from 0.466% to 1.77% during the year ended April
30, 2017.

36 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


The Trust may not declare dividends or make other distributions on its common
shares or purchase any such shares if, at the time of the declaration,
distribution or purchase, the Trust does not comply with the asset coverage
ratios described in the prospectus for the APS.

The APS are redeemable at the option of the Trust, in whole or in part, on any
dividend payment date at $25,000 per share plus any accumulated or unpaid
dividends, whether or not declared. The APS are also subject to mandatory
redemption at $25,000 per share plus any accumulated or unpaid dividends,
whether or not declared, if certain requirements relating to the composition of
the assets and liabilities of the Trust as set forth in the Statement of
Preferences are not satisfied.

The holders of APS have voting rights equal to the holders of the Trust's common
shares (one vote per share) and will vote together with holders of the common
shares as a single class. Holders of APS are also entitled to elect two of the
Trust's Trustees. In addition, the Investment Company Act of 1940, as amended,
requires that along with approval by shareowners that might otherwise be
required, the approval of the holders of a majority of any outstanding preferred
shares, voting separately as a class, would be required to (a) adopt any plan of
reorganization that would adversely affect the preferred shares and (b) take any
action requiring a vote of security holders, including, among other things,
changes in the Trust's subclassification as a closed-end management investment
company or changes in its fundamental investment restrictions.

5. Subsequent Events

A monthly dividend was declared on May 3, 2017 from undistributed and
accumulated net investment income of $0.0500 per common share payable May 31,
2017, to common shareowners of record on May 17, 2017.

Subsequent to April 30, 2017, dividends declared and paid on preferred shares
totaled $161,446 in aggregate for the two outstanding preferred share series
through June 6, 2017.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 37


Report of Independent Registered Public Accounting Firm

To the Board of Trustees and the Shareowners of
Pioneer Municipal High Income Trust:
--------------------------------------------------------------------------------

We have audited the accompanying statement of assets and liabilities, including
the schedule of investments, of Pioneer Municipal High Income Trust (the
"Trust"), as of April 30, 2017, and the related statement of operations for the
year then ended, the statements of changes in net assets for each of the two
years in the period then ended and the financial highlights for each of the
three years in the period then ended. These financial statements and financial
highlights are the responsibility of the Trust's management. Our responsibility
is to express an opinion on these financial statements and financial highlights
based on our audits. The financial highlights for the years ended April 30,
2014, and 2013, were audited by other auditors. Those auditors expressed an
unqualified opinion on those financial highlights in their report dated June 25,
2014.

We conducted our audits in accordance with the standards of the Public Company
Accounting Oversight Board (United States). Those standards require that we plan
and perform the audit to obtain reasonable assurance about whether the financial
statements and financial highlights are free of material misstatement. The Trust
is not required to have, nor were we engaged to perform, an audit of its
internal control over financial reporting. Our audits included consideration of
internal control over financial reporting as a basis for designing audit
procedures that are appropriate in the circumstances, but not for the purpose of
expressing an opinion on the effectiveness of the Trust's internal control over
financial reporting. Accordingly, we express no such opinion. An audit also
includes examining, on a test basis, evidence supporting the amounts and
disclosures in the financial statements, assessing the accounting principles
used and significant estimates made by management, as well as evaluating the
overall financial statement presentation. Our procedures included confirmation
of securities owned as of April 30, 2017, by correspondence with the custodian,
brokers and agent banks; where replies were not received from brokers and agent
banks, we performed other auditing procedures. We believe that our audits
provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to
above present fairly, in all material respects, the financial position of
Pioneer Municipal High Income Trust as of April 30, 2017, and the results of its
operations for the year then ended, the changes in its net assets for each of
the two years in the period then ended and the financial highlights for each of
the three years in the period then ended, in conformity with accounting
principles generally accepted in the United States of America.

/s/ Deloitte & Touche LLP

Boston, Massachusetts
June 19, 2017

38 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


ADDITIONAL INFORMATION

Notice is hereby given in accordance with Section 23(c) of the Investment
Company Act of 1940 that the Trust may purchase, from time to time, its shares
in the open market.

Pioneer Investment Management, Inc. (the "Adviser"), the Trust's investment
adviser, is currently an indirect, wholly owned subsidiary of UniCredit S.p.A.
("UniCredit"). On December 12, 2016, UniCredit announced that it has entered
into a binding agreement for the sale of its Pioneer Investments business, which
includes the Adviser, to Amundi (the "Transaction"). Amundi is headquartered in
Paris, France, and, as of September 30, 2016, had more than $1.1 trillion in
assets under management worldwide. The closing of the Transaction is expected to
happen in 2017, subject to certain regulatory and antitrust approvals, and other
conditions.

Under the Investment Company Act of 1940, the closing of the Transaction will
cause the Trust's current investment advisory agreement with the Adviser to
terminate. Accordingly, the Trust's Board of Trustees has approved a new
investment advisory agreement for the Trust, which has been submitted to the
shareholders of the Trust for their approval.

Change in Independent Registered Public Accounting Firm

Deloitte & Touche LLP, the Trust's independent registered public accounting
firm, has informed the Board that it will no longer be independent with respect
to the Trust upon the completion of the Transaction and, accordingly, that it
intends to resign as the Trust's independent registered public accounting firm
upon the completion of the Transaction. The Board will engage a new independent
registered public accounting firm for the Trust upon the completion of the
Transaction.

During the periods that Deloitte & Touche LLP has served as the Trust's
independent registered public accounting firm, including the Trust's two most
recent fiscal years, Deloitte & Touche LLP's reports on the Trust's financial
statements have not contained an adverse opinion or disclaimer of opinion and
have not been qualified or modified as to uncertainty, audit scope or accounting
principles. Further, there have been no disagreements with Deloitte & Touche LLP
on any matter of accounting principles or practices, financial statement
disclosure, or auditing scope or procedure, which, if not resolved to the
satisfaction of Deloitte & Touche LLP, would have caused Deloitte & Touche LLP
to make reference to the subject matter of the disagreement in connection with
its report on the financial statements. In addition, there have been no
reportable events of the kind described in Item 304(a)(1)(v) of Regulation S-K
under the Securities Exchange Act of 1934.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 39


Approval of New and Interim Management Agreements

Pioneer Investment Management, Inc. (PIM) serves as the investment adviser to
Pioneer Municipal High Income Trust (the Trust) pursuant to an investment
management agreement between PIM and the Trust.

PIM is the principal U.S. asset management business of Pioneer Investments, a
group of companies owned by Pioneer Global Asset Management S.p.A. ("PGAM").
PGAM is a wholly-owned subsidiary of UniCredit S.p.A. ("UniCredit"). UniCredit
and PGAM have entered into a binding agreement to sell Pioneer Investments,
including PIM, to Amundi (the "Transaction"). Upon the consummation of the
transaction, PIM will become an indirect wholly-owned subsidiary of Amundi and
Amundi's wholly-owned subsidiary, Amundi USA, Inc. The closing of the
Transaction is expected to happen in 2017.

Under the Investment Company Act of 1940, the Trust's current investment
management agreement (the "Current Management Agreement") will terminate
automatically upon the consummation of the Transaction. In order for PIM to
continue to manage the Trust after the consummation of the Transaction, the
Trustees and shareholders of the Trust must approve a new investment management
agreement for the Trust (the "New Management Agreement"). As discussed below,
the Board of Trustees of the Trust approved the New Management Agreement at a
meeting held on March 6-7, 2017. The New Management Agreement has been submitted
to the shareholders of the Trust for their approval at a meeting to be held on
June 13, 2017. If the shareholders of the Trust do not approve the New
Management Agreement and the Transaction is completed, an interim investment
management agreement between PIM and the Trust (the "Interim Management
Agreement") will take effect upon the closing of the Transaction. The Board of
Trustees of the Trust also approved the Interim Management Agreement at the
March 6-7, 2017 meeting.

Board Evaluation of the New and Interim Management Agreements

The Board evaluated the Transaction and the New Management Agreement and Interim
Management Agreement for the Trust. In connection with their evaluation of the
Transaction and the New Management Agreement for the Trust, the Trustees
requested such information as they deemed reasonably necessary, including: (a)
the structure of the Transaction and the strategy underlying the Transaction;
(b) the anticipated benefits of the Transaction to the Trust and its
shareholders; (c) the post-Transaction plans for PIM, including Amundi's plans
for integration of Pioneer Investments and PIM with its existing asset
management businesses and plans for the future development of PIM; (d) the
effect of the Transaction on the ongoing services provided to the Trust,
including the need to select a new independent registered public

40 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


accounting firm for the Trust, and any plans to modify the operations of the
Trust; (e) the stability and continuity of PIM's management and key employees,
including compensation and benefits to PIM's key employees, and retention plans
and incentive plan structure; (f) the post-Transaction indebtedness and
financial resources of PIM; (g) Amundi's legal and operational structure, its
principal shareholders and senior management, its investment management, risk
management, administrative, legal and compliance functions; (h) certain
regulatory matters relating to Amundi's affiliates; and (i) Amundi's commitment
to the United States, including the role of PIM in the larger Amundi business.

The Trustees also requested and obtained the following information in connection
with their evaluation of the Transaction and the New Management Agreement for
the Trust: (i) memoranda provided by Fund counsel that summarized the legal
standards and other considerations that are relevant to the Trustees in their
deliberations regarding the New Management Agreement; (ii) the qualifications of
the investment management teams for the Trust, as well as the level of
investment by the Trust's portfolio managers in the Trust; (iii) the Trust's
management fees and total expense ratios, the financial statements of PIM and
its pre- and post-Transaction parent companies, profitability analyses from PIM,
and analyses from PIM as to possible economies of scale; (iv) the profitability
of the institutional business of PIM and PIM's affiliate, Pioneer Institutional
Asset Management, Inc. ("PIAM") as compared to that of PIM's fund management
business; and (v) the differences between the fees and expenses of the Trust and
the fees and expenses of PIM's and PIAM's institutional accounts, as well as the
different services provided by Adviser to the Trust and by PIM and PIAM to the
institutional accounts. In addition, the Trustees considered the information
provided at regularly scheduled meetings throughout the year regarding the
Trust's performance and risk attributes, including through meetings with
investment management personnel, and took into account other information related
to the Trust provided to the Trustees at regularly scheduled meetings. The
Trustees also considered information they had received in their review of the
continuance of the Current Management Agreement for the Trust in September 2016.

At meetings held on January 9, 2017 and January 10, 2017, the Trustees met with
representatives of Amundi and PGAM, including separate meetings of the Trustees
who are not "interested persons" of the Fund Complex ("Independent Trustees")
and counsel with representatives of Amundi and PGAM, and subsequently with
representatives of Amundi. In those meetings, they received an extensive
presentation from the representatives of Amundi, including the chief executive
officer of Amundi, describing Amundi's background and history, its global asset
management activities, the growth of its business, and its status as the largest
asset management firm in Europe and

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 41


one of the largest globally; its capital structure and financial resources,
including information as to the financing of the Transaction; its principal
investors, including its majority investor Credit Agricole S.A., and Credit
Agricole's long-term commitment to the asset management business; the philosophy
and strategy underlying the Transaction and the complementarity of Amundi's and
Pioneer Investments' respective asset management businesses; Amundi's various
operating and investment committees and how they would likely interact with PIM;
the proposed integration process, including the progress to date and the
establishment of various integration work streams; Amundi's plans for management
of PIM; Amundi's philosophy as to compensation of key employees and its general
intentions with respect to incentive plans for key employees of PIM; Amundi's
preliminary plans to achieve cost and other synergies; and opportunities to
further develop the business of PIM and PIAM, including in the area of
institutional asset management, and how that would benefit shareholders of the
Pioneer Funds.

In those meetings, the representatives of Amundi confirmed their intention that
the Chief Executive Officer and Chief Investment Officer of PIM would remain in
their current positions, and confirmed that they do not currently foresee major
changes in the day-to-day investment management operations of PIM with respect
to the Trust as a direct result of the Transaction. They discussed incentive
arrangements for key personnel that would continue after the closing of the
Transaction and their plans to establish a new long-term incentive plan
following the closing. They also generally discussed ways in which PIM could
potentially draw on the expanded global resources of Amundi post-Transaction. At
those meetings, the Independent Trustees identified certain areas to which they
requested further information, including as to trading and execution of
securities transactions, research and portfolio management and potential changes
in investment process, particularly where asset classes managed by PIM would
overlap with asset classes managed by Amundi, the continued availability of
resources currently at Pioneer Investments or elsewhere within Amundi to assist
in management of certain Funds, and any anticipated significant changes in
operations. The Independent Trustees considered the uncertainty as to whether
the Trust's independent registered public accounting firm could continue to act
in that capacity after the closing of the Transaction. The Independent Trustees
also met with counsel to review the information they had received to date and to
discuss next steps.

Subsequently, the Trustees received further information from Amundi, including
written responses to questions raised by the Independent Trustees, and received
from PIM the information requested of it. The Independent Trustees reviewed the
information provided with counsel at telephonic meetings held on February 16,
2017 and February 27, 2017. The Trustees held a special in-person Board meeting
on March 6-7, 2017 for further

42 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


consideration of the New Management Agreements, the Interim Management
Agreements and the Transaction. The Trustees met again with senior executives of
Amundi at the March 6-7, 2017 meeting.

At the March 6-7, 2017 meeting, based on their evaluation of the information
provided by PIM and Amundi, the Trustees including the Independent Trustees
voting separately, approved the New Management Agreement and the Interim
Management Agreement for the Trust. In considering the New Management Agreement
for the Trust, the Trustees considered various factors that they determined were
relevant, including the factors described below. The Trustees did not identify
any single factor as the controlling factor in their determinations. The
Trustees considered the same factors with respect to the Interim Management
Agreement for the Trust.

Nature, Extent and Quality of Services

The Trustees considered the nature, extent and quality of the services that had
been provided by PIM to the Trust and that are expected to be provided by PIM to
the Trust following the consummation of the Transaction. The Trustees reviewed
the terms of the New Management Agreement, and noted that such terms are
substantially similar to the terms of the Current Management Agreement, except
for different execution dates, effective dates and termination dates. The
Trustees reviewed PIM's investment approach for the Trust and its research
process. The Trustees considered the resources of PIM and the personnel of PIM
who provide investment management services to the Trust. They also reviewed the
amount of non-investment resources and personnel of PIM that are involved in
PIM's services to the Trust, including PIM's compliance and legal resources and
personnel. The Trustees noted the substantial attention and high priority given
by PIM's senior management to the Pioneer Fund complex.

The Trustees considered that PIM supervises and monitors the performance of the
Trust's service providers and provides the Trust with personnel (including Fund
officers) and other resources that are necessary for the Trust's business
management and operations and that PIM would continue to provide those
investment management and research services and resources to the Trust following
the consummation of the Transaction. The Trustees also considered that, as
administrator, PIM would continue to be responsible for the administration of
the Trust's business and other affairs. The Trustees considered the fees to be
paid to PIM for the provision of administration services.

The Trustees considered that Deloitte & Touche LLP has informed the Board that
it will no longer be independent with respect to the Trust upon the completion
of the Transaction and, accordingly, that it will be necessary for the Board to
engage a new independent registered public accounting firm for the Trust.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 43


The Trustees considered that the Transaction is not expected to have a material
adverse impact on the nature, scope and overall quality of services provided to
the Trust and its shareholders, including investment management, risk
management, administrative, compliance, legal and other services, as a result of
the Transaction.

In that regard, the Trustees considered that Amundi is one of the largest asset
managers globally, and that PIM may have access to additional research and
portfolio management capabilities as a result of the Transaction and that PIM,
as part of Amundi, is expected to have an enhanced global presence that may
contribute to an increase in the overall scale and resources of PIM.
Furthermore, in considering whether the Transaction would be expected to have a
material adverse impact on the nature, scope and overall quality of services
provided to the Trust and its shareholders, the Trustees considered the
statements by representatives of Amundi that they expect the Chief Executive
Officer and Chief Investment Officer of PIM to remain in their current positions
and that they do not currently foresee major changes in the day-to-day
investment management operations of PIM as a direct result of the Transaction,
or the risk management, legal or compliance services provided by PIM, with
respect to the Trust. They further considered the current incentive arrangements
for key personnel of PIM that would continue after the closing of the
Transaction. They also noted Amundi's stated intention to establish a new
long-term incentive plan following the closing.

The Trustees also took into account their experience in evaluating the proposed
combination of Pioneer Investments and Santander Asset Management, which was
announced in September, 2014 and abandoned in July, 2016. In light of, among
other things, this experience, the Trustees determined that they were not able
to identify any realistic alternatives to approving the New Management Agreement
that would provide the level of services to the Trust and its shareholders that
are expected to be provided by PIM after the closing of the Transaction.

Based on these considerations, the Trustees concluded that the nature, extent
and quality of services that PIM would continue to provide to the Trust under
the New Management Agreement would be satisfactory and consistent with the terms
of the New Management Agreement.

Performance of the Trust

In considering the Trust's performance, the Trustees regularly reviewed and
discussed throughout the year data prepared by PIM and information comparing the
Trust's performance with the performance of its peer group of funds, as
classified by each of Morningstar, Inc. (Morningstar) and Lipper, and the
performance of the Trust's benchmark index. They also discussed the Trust's
performance with PIM on a regular basis.

44 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


The Trustees' regular reviews and discussions were factored into the Trustees'
deliberations concerning the approval of the New Management Agreement.

Management Fee and Expenses

The Trustees noted that the stated management fees to be paid by the Trust are
identical under the Current Management Agreement and the New Management
Agreement. The Trustees considered information showing the fees and expenses of
the Trust in comparison to the management fees and expense ratios of its peer
group of funds as classified by Morningstar and also to the expense ratios of a
peer group of funds selected on the basis of criteria determined by the
Independent Trustees for this purpose using data provided by Strategic Insight
Mutual Fund Research and Consulting, LLC (Strategic Insight), an independent
third party. In all quintile rankings referred to below, first quintile is most
favorable to the Trust's shareowners. To the extent applicable, the Trustees
also considered the impact of transfer agency, sub-transfer agency, and other
non-management fee expenses on the expense ratios of the Trust. The Trustees
noted that they separately review the Trust's transfer agency, sub-transfer
agency and intermediary arrangements and that the results of the most recent
such review were considered in the consideration of the Trust's expense ratio.

The Trustees considered that the Fund's management fee (based on managed assets)
as of September 30, 2016 was in the fourth quintile relative to the management
fees paid by other funds in its Strategic Insight peer group for the comparable
period. The Trustees considered that the Trust's management fee was
approximately five basis points higher than the median management fee paid by
other funds in its Morningstar category. The Trustees considered that the
expense ratio (based on managed assets) of the Trust's common shares as of
September 30, 2016 was in the third quintile relative to its Strategic Insight
peer group for the comparable period.

The Trustees reviewed management fees charged by PIM and PIAM to institutional
and other clients, including publicly offered European funds sponsored by PIM's
affiliates, unaffiliated U.S. registered investment companies (in a sub-advisory
capacity), and unaffiliated foreign and domestic separate accounts. The Trustees
also considered PIM's costs in providing services to the Trust and PIM's and
PIAM's costs in providing services to the other clients and considered the
differences in management fees and profit margins for fund and non-fund
services. In evaluating the fees associated with PIM's and PIAM's client
accounts, the Trustees took into account the respective demands, resources and
complexity associated with the Trust and other client accounts. The Trustees
noted that in some instances the fee rates for those clients were lower than the
management fee for the Trust and considered that, under both the Current
Management Agreement and the New Management Agreement,

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 45


PIM would perform additional services for the Trust that it does not provide to
those other clients or services that are broader in scope, including oversight
of the Trust's other service providers and activities related to compliance and
the extensive regulatory and tax regimes to which the Trust is subject. The
Trustees also considered the different risks associated with PIM's management of
the Trust and PIM's and PIAM's management of the other client accounts.

The Trustees concluded that the management fee payable by the Trust to PIM was
reasonable in relation to the nature and quality of the services to be provided
by PIM.

Profitability

The Trustees considered information provided by PIM regarding the profitability
of PIM with respect to the advisory services provided by PIM to the Trust,
including the methodology used by PIM in allocating certain of its costs to the
management of the Trust. The Trustees also considered PIM's profit margin in
connection with the overall operation of the Trust. They further reviewed the
financial results, including the profit margins, realized by PIM and PIAM from
non-fund businesses. The Trustees considered PIM's profit margins with respect
to the Trust in comparison to the limited industry data available and noted that
the profitability of any adviser was affected by numerous factors, including its
organizational structure and method for allocating expenses. The Trustees
concluded that PIM's profitability with respect to the management of the Trust
was not unreasonable.

Economies of Scale

The Trustees considered PIM's views relating to economies of scale in connection
with the Pioneer Funds as fund assets grow and the extent to which any such
economies of scale are shared with the Trust and Fund shareholders. The Trustees
recognize that economies of scale are difficult to identify and quantify, and
that, among other factors that may be relevant, are the following: fee levels,
expense subsidization, investment by PIM in research and analytical capabilities
and PIM's commitment and resource allocation to the Trust. The Trustees noted
that profitability also may be an indicator of the availability of any economies
of scale, although profitability may vary for other reasons including due to
reductions in expenses. The Trustees concluded that economies of scale, if any,
were being appropriately shared with the Trust.

46 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Other Benefits

The Trustees considered the other benefits that PIM enjoys from its relationship
with the Trust. The Trustees considered the character and amount of fees paid or
to be paid by the Trust, other than under the Current Management Agreement or
the New Management Agreement, for services provided by PIM and its affiliates.
The Trustees further considered the revenues and profitability of PIM's
businesses other than the Fund business. To the extent applicable, the Trustees
also considered the benefits to the Trust and to PIM and its affiliates from the
use of "soft" commission dollars generated by the Trust to pay for research and
brokerage services.

The Trustees considered that following the completion of the Transaction, PIM
will be the principal U.S. asset management business of Amundi, and that
Amundi's worldwide asset management business will manage over $1.38 trillion in
assets (including the Pioneer Funds). This may create opportunities for PIM,
PIAM and Amundi that derive from PIM's relationships with the Trust, including
Amundi's ability to market the services of PIM globally. The Trustees noted that
PIM may have access to additional research capabilities as a result of the
Transaction and Amundi's enhanced global presence that may contribute to an
increase of the overall scale of PIM. The Trustees considered that PIM and the
Trust are expected to receive reciprocal intangible benefits from the
relationship, including mutual brand recognition and, for the Trust, direct and
indirect access to the resources of a large global asset manager. The Trustees
concluded that any such benefits received by PIM as a result of its relationship
with the Trust were reasonable.

Conclusion

After consideration of the factors described above as well as other factors, the
Trustees, including the Independent Trustees, concluded that the New Management
Agreement and the Interim Management Agreement for the Trust, including the fees
payable thereunder, were fair and reasonable and voted to approve the New
Management Agreement and the Interim Management Agreement, and to recommend that
shareholders approve the New Management Agreement.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 47


Trustees, Officers and Service Providers

Investment Adviser
Pioneer Investment Management, Inc.

Custodian and Sub-Administrator
Brown Brothers Harriman & Co.

Independent Registered Public Accounting Firm
Deloitte & Touche LLP

Principal Underwriter
Pioneer Funds Distributor, Inc.

Legal Counsel
Morgan, Lewis & Bockius LLP

Shareowner Services and Transfer Agent
American Stock Transfer & Trust Company

Proxy Voting Policies and Procedures of the Fund are available without charge,
upon request, by calling our toll free number (1-800-225-6292). Information
regarding how the Fund voted proxies relating to portfolio securities during the
most recent 12-month period ended June 30 is publicly available to shareowners
at us.pioneerinvestments.com. This information is also available on the
Securities and Exchange Commission's web site at www.sec.gov.

Trustees and Officers

The Trust's Trustees and officers are listed below, together with their
principal occupations during at least the past five years. Trustees who are
interested persons of the Trust within the meaning of the 1940 Act are referred
to as Interested Trustees. Trustees who are not interested persons of the Trust
are referred to as Independent Trustees. Each of the Trustees serves as a
trustee of each of the 46 U.S. registered investment portfolios for which
Pioneer serves as investment adviser (the "Pioneer Funds"). The address for all
Trustees and all officers of the Trust is 60 State Street, Boston, Massachusetts
02109.

The Statement of Additional Information of the Fund includes additional
information about the Trustees and is available, without charge, upon request,
by calling 1-800-225-6292.

48 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Independent Trustees



------------------------------------------------------------------------------------------------------------------------------------
Name, Age and                 Term of Office and                                                     Other Directorships
Position Held With the Trust  Length of Service   Principal Occupation                               Held by Trustee
------------------------------------------------------------------------------------------------------------------------------------
                                                                                            
Thomas J. Perna (66)          Class III Trustee   Private investor (2004 - 2008 and 2013 -           Director, Broadridge Financial
Chairman of the Board         since 2006. Term    present); Chairman (2008 - 2013) and Chief         Solutions, Inc. (investor
and Trustee                   expires in 2018.    Executive Officer (2008 - 2012), Quadriserv,       communications and securities
                                                  Inc. (technology products for securities lending   processing provider for
                                                  industry); and Senior Executive Vice President,    financial services industry)
                                                  The Bank of New York (financial and securities     (2009 - present); Director,
                                                  services) (1986 - 2004)                            Quadriserv, Inc. (2005 - 2013);
                                                                                                     and Commissioner, New Jersey
                                                                                                     State Civil Service Commission
                                                                                                     (2011 - 2015)
------------------------------------------------------------------------------------------------------------------------------------
David R. Bock (73)            Class I Trustee     Managing Partner, Federal City Capital Advisors    Director of New York Mortgage
Trustee                       since 2005. Term    (corporate advisory services company) (1997 -      Trust (publicly-traded mortgage
                              expires in 2019.    2004 and 2008 - present); Interim Chief            REIT) (2004 - 2009, 2012 -
                                                  Executive Officer, Oxford Analytica, Inc.          present); Director of The Swiss
                                                  (privately-held research and consulting company)   Helvetia Fund, Inc. (closed-end
                                                  (2010); Executive Vice President and Chief         fund) (2010 - present);
                                                  Financial Officer, I-trax, Inc. (publicly traded   Director of Oxford Analytica,
                                                  health care services company) (2004 - 2007); and   Inc. (2008 - present); and
                                                  Executive Vice President and Chief Financial       Director of Enterprise
                                                  Officer, Pedestal Inc. (internet-based mortgage    Community Investment, Inc.
                                                  trading company) (2000 - 2002); Private            (privately-held affordable
                                                  consultant (1995-1997), Managing Director,         housing finance company) (1985
                                                  Lehman Brothers (investment banking firm)          - 2010)
                                                  (1992-1995); and Executive, The World Bank
                                                  (1979-1992)
------------------------------------------------------------------------------------------------------------------------------------
Benjamin M. Friedman (72)     Class II Trustee    William Joseph Maier Professor of Political        Trustee, Mellon Institutional
Trustee                       since 2008. Term    Economy, Harvard University (1972 - present)       Funds Investment Trust and
                              expires in 2017.                                                       Mellon Institutional Funds
                                                                                                     Master Portfolio (oversaw 17
                                                                                                     portfolios in fund complex)
                                                                                                     (1989-2008)
------------------------------------------------------------------------------------------------------------------------------------


                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 49


Independent Trustees (continued)



----------------------------------------------------------------------------------------------------------------------------------
Name, Age and                 Term of Office and                                                     Other Directorships
Position Held With the Trust  Length of Service   Principal Occupation                               Held by Trustee
------------------------------------------------------------------------------------------------------------------------------------
                                                                                            
Margaret B.W. Graham (69)     Class II Trustee    Founding Director, Vice President and Corporate    None
Trustee                       since 2003. Term    Secretary, The Winthrop Group, Inc. (consulting
                              expires in 2017.    firm) (1982 - present); Desautels Faculty of
                                                  Management, McGill University (1999 - present);
                                                  and Manager of Research Operations and
                                                  Organizational Learning, Xerox PARC, Xerox's
                                                  advance research center (1990-1994)
------------------------------------------------------------------------------------------------------------------------------------
Lorraine H. Monchak (61)      Class I Trustee     Chief Investment Officer, 1199 SEIU Funds          None
Trustee                       since 2015. Term    (healthcare workers union pension funds) (2001 -
                              expires in 2019.    present); Vice President - International
                                                  Investments Group, American International Group,
                                                  Inc. (insurance company) (1993 - 2001); Vice
                                                  President Corporate Finance and Treasury Group,
                                                  Citibank, N.A. (1980 - 1986 and 1990 - 1993);
                                                  Vice President - Asset/Liability Management
                                                  Group, Federal Farm Funding Corporation
                                                  (government-sponsored issuer of debt securities)
                                                  (1988 - 1990); Mortgage Strategies Group,
                                                  Shearson Lehman Hutton, Inc. (investment bank)
                                                  (1987 - 1988); and Mortgage Strategies Group,
                                                  Drexel Burnham Lambert, Ltd. (investment bank)
                                                  (1986 - 1987)
------------------------------------------------------------------------------------------------------------------------------------
Marguerite A. Piret (68)      Class III Trustee   President and Chief Executive Officer, Newbury     Director of New America High
Trustee                       since 2003. Term    Piret Company (investment banking firm) (1981 -    Income Fund, Inc. (closed-end
                              expires in 2018.    present)                                           investment company) (2004 -
                                                                                                     present); and Member, Board of
                                                                                                     Governors, Investment Company
                                                                                                     Institute (2000 - 2006)
------------------------------------------------------------------------------------------------------------------------------------
Fred J. Ricciardi (70)        Class III Trustee   Consultant (investment company services) (2012 -   None
Trustee                       since 2014. Term    present); Executive Vice President, BNY Mellon
                              expires in 2018.    (financial and investment company services)
                                                  (1969 - 2012); Director, BNY International
                                                  Financing Corp. (financial services) (2002 -
                                                  2012); and Director, Mellon Overseas Investment
                                                  Corp. (financial services) (2009 - 2012)
------------------------------------------------------------------------------------------------------------------------------------


50 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


Interested Trustees



------------------------------------------------------------------------------------------------------------------------------------
Name, Age and                 Term of Office and                                                     Other Directorships
Position Held With the Trust  Length of Service   Principal Occupation                               Held by Trustee
------------------------------------------------------------------------------------------------------------------------------------
                                                                                            
Lisa M. Jones (55)*           Class I Trustee     Chair, Director, CEO and President of Pioneer      None
Trustee, President and        since 2015. Term    Investment Management-USA (PIM-USA) (since
Chief Executive Officer       expires in 2019.    September 2014); Chair, Director, CEO and
                                                  President of Pioneer Investment Management, Inc.
                                                  (since September 2014); Chair, Director, CEO and
                                                  President of Pioneer Funds Distributor, Inc.
                                                  (since September 2014); Chair, Director, CEO and
                                                  President of Pioneer Institutional Asset
                                                  Management, Inc. (since September 2014); and
                                                  Chair, Director, and CEO of Pioneer Investment
                                                  Management Shareholder Services, Inc. (since
                                                  September 2014); Managing Director, Morgan
                                                  Stanley Investment Management (2010 - 2013); and
                                                  Director of Institutional Business, CEO of
                                                  International, Eaton Vance Management (2005 -
                                                  2010)
------------------------------------------------------------------------------------------------------------------------------------
Kenneth J. Taubes (59)*       Class II Trustee    Director and Executive Vice President (since       None
Trustee                       since 2014. Term    2008) and Chief Investment Officer, U.S. (since
                              expires in 2017.    2010) of PIM-USA; Executive Vice President of
                                                  Pioneer (since 2008); Executive Vice President of
                                                  Pioneer Institutional Asset Management, Inc.
                                                  (since 2009); and Portfolio Manager of Pioneer
                                                  (since 1999)
------------------------------------------------------------------------------------------------------------------------------------


*    Ms. Jones and Mr. Taubes are Interested Trustees because they are officers
     or directors of the Trust's investment adviser and certain of its
     affiliates.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 51


Trust Officers



------------------------------------------------------------------------------------------------------------------------------------
Name, Age and                 Term of Office and                                                     Other Directorships
Position Held With the Trust  Length of Service   Principal Occupation                               Held by Officer
------------------------------------------------------------------------------------------------------------------------------------
                                                                                            
Christopher J. Kelley         Since 2003. Serves  Vice President and Associate General Counsel of    None
(52)                          at the discretion   Pioneer since January 2008; Secretary and Chief
Secretary and                 of the Board.       Legal Officer of all of the Pioneer Funds since
Chief Legal Officer                               June 2010; Assistant Secretary of all of the
                                                  Pioneer Funds from September 2003 to May 2010;
                                                  and Vice President and Senior Counsel of Pioneer
                                                  from July 2002 to December 2007
------------------------------------------------------------------------------------------------------------------------------------
Carol B. Hannigan (56)        Since 2010. Serves  Fund Governance Director of Pioneer since          None
Assistant Secretary           at the discretion   December 2006 and Assistant Secretary of all the
                              of the Board.       Pioneer Funds since June 2010; Manager - Fund
                                                  Governance of Pioneer from December 2003 to
                                                  November 2006; and Senior Paralegal of Pioneer
                                                  from January 2000 to November 2003
------------------------------------------------------------------------------------------------------------------------------------
Thomas Reyes (54)             Since 2010. Serves  Senior Counsel of Pioneer since May 2013 and       None
Assistant Secretary           at the discretion   Assistant Secretary of all the Pioneer Funds
                              of the Board.       since June 2010; and Counsel of Pioneer from June
                                                  2007 to May 2013
------------------------------------------------------------------------------------------------------------------------------------
Mark E. Bradley (57)          Since 2008. Serves  Vice President - Fund Treasury of Pioneer;         None
Treasurer and Chief           at the discretion   Treasurer of all of the Pioneer Funds since March
Financial                     of the Board.       2008; Deputy Treasurer of Pioneer from March 2004
and Accounting Officer                            to February 2008; and Assistant Treasurer of all
                                                  of the Pioneer Funds from March 2004 to February
                                                  2008
------------------------------------------------------------------------------------------------------------------------------------
Luis I. Presutti (52)         Since 2003. Serves  Director - Fund Treasury of Pioneer; and           None
Assistant Treasurer           at the discretion   Assistant Treasurer of all of the Pioneer Funds
                              of the Board.
------------------------------------------------------------------------------------------------------------------------------------
Gary Sullivan (59)            Since 2003. Serves  Fund Accounting Manager - Fund Treasury of         None
Assistant Treasurer           at the discretion   Pioneer; and Assistant Treasurer of all of the
                              of the Board.       Pioneer Funds
------------------------------------------------------------------------------------------------------------------------------------


52 Pioneer Municipal High Income Trust | Annual Report | 4/30/17




------------------------------------------------------------------------------------------------------------------------------------
Name, Age and                 Term of Office and                                                     Other Directorships
Position Held With the Trust  Length of Service   Principal Occupation                               Held by Officer
------------------------------------------------------------------------------------------------------------------------------------
                                                                                            
David F. Johnson (37)         Since 2009. Serves  Fund Administration Manager - Fund Treasury of     None
Assistant Treasurer           at the discretion   Pioneer since November 2008; Assistant Treasurer
                              of the Board.       of all of the Pioneer Funds since January 2009;
                                                  and Client Service Manager - Institutional
                                                  Investor Services at State Street Bank from March
                                                  2003 to March 2007
------------------------------------------------------------------------------------------------------------------------------------
Jean M. Bradley (64)          Since 2010. Serves  Chief Compliance Officer of Pioneer and of all the None
Chief Compliance Officer      at the discretion   Pioneer Funds since March 2010; Chief Compliance
                              of the Board.       Officer of Pioneer Institutional Asset Management,
                                                  Inc. since January 2012; Chief Compliance Officer
                                                  of Vanderbilt Capital Advisors, LLC since July
                                                  2012: Director of Adviser and Portfolio Compliance
                                                  at Pioneer since October 2005; and Senior
                                                  Compliance Officer for Columbia Management
                                                  Advisers, Inc. from October 2003 to October 2005
------------------------------------------------------------------------------------------------------------------------------------
Kelly O'Donnell (46)          Since 2006. Serves  Director - Transfer Agency Compliance of Pioneer   None
Anti-Money Laundering         at the discretion   and Anti-Money Laundering Officer of all the
Officer                       of the Board.       Pioneer Funds since 2006
------------------------------------------------------------------------------------------------------------------------------------


                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 53


                          This page is for your notes.

54 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


                          This page is for your notes.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 55


                          This page is for your notes.

56 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


                          This page is for your notes.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 57


                          This page is for your notes.

58 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


                          This page is for your notes.

                Pioneer Municipal High Income Trust | Annual Report | 4/30/17 59


                          This page is for your notes.

60 Pioneer Municipal High Income Trust | Annual Report | 4/30/17


How to Contact Pioneer

We are pleased to offer a variety of convenient ways for you to contact us for
assistance or information.

You can call American Stock Transfer & Trust Company (AST) for:
--------------------------------------------------------------------------------

Account Information                                      1-800-710-0935

Or write to AST:
--------------------------------------------------------------------------------
For                                                      Write to

General inquiries, lost dividend checks,                 American Stock
change of address, lost stock certificates,              Transfer & Trust
stock transfer                                           Operations Center
                                                         6201 15(th) Ave.
                                                         Brooklyn, NY 11219

Dividend reinvestment plan (DRIP)                        American Stock
                                                         Transfer & Trust
                                                         Wall Street Station
                                                         P.O. Box 922
                                                         New York, NY 10269-0560

Website www.amstock.com

For additional information, please contact your investment advisor or visit our
web site us.pioneerinvestments.com.

The Trust files a complete schedule of investments with the Securities and
Exchange Commission for the first and third quarters for each fiscal year on
Form N-Q. Shareowners may view the filed Form N-Q by visiting the Commission's
web site at www.sec.gov. The filed form may also be viewed and copied at the
Commission's Public Reference Room in Washington, DC. Information regarding the
operations of the Public Reference Room may be obtained by calling
1-800-SEC-0330.


[LOGO] PIONEER
       Investments(R)

Pioneer Investment Management, Inc.
60 State Street
Boston, MA 02109
us.pioneerinvestments.com

Securities offered through Pioneer Funds Distributor, Inc.
60 State Street, Boston, MA 02109
Underwriter of Pioneer Mutual Funds, Member SIPC
(C) 2017 Pioneer Investments 19384-11-0617






ITEM 2. CODE OF ETHICS.

(a) Disclose whether, as of the end of the period covered by the report, the
registrant has adopted a code of ethics that applies to the registrant's
principal executive officer, principal financial officer, principal accounting
officer or controller, or persons performing similar functions, regardless of
whether these individuals are employed by the registrant or a third party.  If
the registrant has not adopted such a code of ethics, explain why it has not
done so.

The registrant has adopted, as of the end of the period covered by this report,
a code of ethics that applies to the registrant's principal executive officer,
principal financial officer, principal accounting officer and controller.

(b) For purposes of this Item, the term "code of ethics" means written standards
that are reasonably designed to deter wrongdoing and to promote:

        (1) Honest and ethical conduct, including the ethical handling of actual
        or apparent conflicts of interest between personal and professional
        relationships;

        (2) Full, fair, accurate, timely, and understandable disclosure in
        reports and documents that a registrant files with, or submits to, the
        Commission and in other public communications made by the registrant;

        (3) Compliance with applicable governmental laws, rules, and
        regulations;

        (4) The prompt internal reporting of violations of the code to an
        appropriate person or persons identified in the code; and

        (5) Accountability for adherence to the code.

(c) The registrant must briefly describe the nature of any amendment, during the
period covered by the report, to a provision of its code of ethics that applies
to the registrant's principal executive officer, principal financial officer,
principal accounting officer or controller, or persons performing similar
functions, regardless of whether these individuals are employed by the
registrant or a third party, and that relates to any element of the code of
ethics definition enumerated in paragraph (b) of this Item. The registrant must
file a copy of any such amendment as an exhibit pursuant to Item 10(a), unless
the registrant has elected to satisfy paragraph (f) of this Item by posting its
code of ethics on its website pursuant to paragraph (f)(2) of this Item, or by
undertaking to provide its code of ethics to any person without charge, upon
request, pursuant to paragraph (f)(3) of this Item.

The registrant has made no amendments to the code of ethics during the period
covered by this report.

(d) If the registrant has, during the period covered by the report, granted a
waiver, including an implicit waiver, from a provision of the code of ethics to
the registrant's principal executive officer, principal financial officer,
principal accounting officer or controller, or persons performing similar
functions, regardless of whether these individuals are employed by the
registrant or a third party, that relates to one or more of the items set forth
in paragraph (b) of this Item, the registrant must briefly describe the nature
of the waiver, the name of the person to whom the waiver was granted, and the
date of the waiver.

Not applicable.

(e) If the registrant intends to satisfy the disclosure requirement under
paragraph (c) or (d) of this Item regarding an amendment to, or a waiver from,
a provision of its code of ethics that applies to the registrant's principal
executive officer, principal financial officer, principal accounting officer or
controller, or persons performing similar functions and that relates to any
element of the code of ethics definition enumerated in paragraph (b) of this
Item by posting such information on its Internet website, disclose the
registrant's Internet address and such intention.

Not applicable.

(f) The registrant must:

        (1) File with the Commission, pursuant to Item 12(a)(1), a copy of
        its code of ethics that applies to the registrant's principal
        executive officer,principal financial officer, principal accounting
        officer or controller, or persons performing similar functions,
        as an exhibit to its annual
        report on this Form N-CSR (see attachment);

        (2) Post the text of such code of ethics on its Internet website and
        disclose, in its most recent report on this Form N-CSR, its Internet
        address and the fact that it has posted such code of ethics on its
        Internet website; or

        (3) Undertake in its most recent report on this Form N-CSR to provide to
        any person without charge, upon request, a copy of such code of ethics
        and explain the manner in which such request may be made.
	See Item 10(2)

ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

(a) (1)  Disclose that the registrant's board of trustees has determined that
         the registrant either:

    (i)  Has at least one audit committee financial expert serving on its audit
         committee; or

    (ii) Does not have an audit committee financial expert serving on its audit
         committee.

The registrant's Board of Trustees has determined that the registrant has at
least one audit committee financial expert.

    (2) If the registrant provides the disclosure required by paragraph
(a)(1)(i) of this Item, it must disclose the name of the audit committee
financial expert and whether that person is "independent." In order to be
considered "independent" for purposes of this Item, a member of an audit
committee may not, other than in his or her capacity as a member of the audit
committee, the board of trustees, or any other board committee:

    (i)  Accept directly or indirectly any consulting, advisory, or other
         compensatory fee from the issuer; or

    (ii) Be an "interested person" of the investment company as defined in
         Section 2(a)(19) of the Act (15 U.S.C. 80a-2(a)(19)).

Ms. Marguerite A. Piret, an independent trustee, is such an audit committee
financial expert.

    (3) If the registrant provides the disclosure required by paragraph (a)(1)
(ii) of this Item, it must explain why it does not have an audit committee
financial expert.

Not applicable.


ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

(a) Disclose, under the caption AUDIT FEES, the aggregate fees billed for each
of the last two fiscal years for professional services rendered by the principal
accountant for the audit of the registrant's annual financial statements or
services that are normally provided by the accountant in connection with
statutory and regulatory filings or engagements for those fiscal years.

The audit fees for the Trust were $51,534
payable to Deloitte & Touche LLP for the year ended
April 30, 2017 and $48,643 for the year ended April 30, 2016.


(b) Disclose, under the caption AUDIT-RELATED FEES, the aggregate fees billed in
each of the last two fiscal years for assurance and related services by the
principal accountant that are reasonably related to the performance of the audit
of the registrant's financial statements and are not reported under
paragraph (a) of this Item. Registrants shall describe the nature of the
services comprising the fees disclosed under this category.

There were no audit-related services in 2017 or 2016.


(c) Disclose, under the caption TAX FEES, the aggregate fees billed in each of
the last two fiscal years for professional services rendered by the principal
accountant for tax compliance, tax advice, and tax planning. Registrants shall
describe the nature of the services comprising the fees disclosed under this
category.

The tax fees for the Trust were $9,904
payable to Deloitte & Touche LLP for the year ended
April 30, 2017 and $9,876 for the year ended April 30, 2016.

(d) Disclose, under the caption ALL OTHER FEES, the aggregate fees billed in
each of the last two fiscal years for products and services provided by the
principal accountant, other than the services reported in paragraphs (a) through
(c) of this Item. Registrants shall describe the nature of the services
comprising the fees disclosed under this category.

There were no other fees in 2017 or 2016.

(e) (1) Disclose the audit committee's pre-approval policies and procedures
described in paragraph (c)(7) of Rule 2-01 of Regulation S-X.

 PIONEER FUNDS
            APPROVAL OF AUDIT, AUDIT-RELATED, TAX AND OTHER SERVICES
                       PROVIDED BY THE INDEPENDENT AUDITOR

                  SECTION I - POLICY PURPOSE AND APPLICABILITY

The Pioneer Funds recognize the importance of maintaining the independence of
their outside auditors. Maintaining independence is a shared responsibility
involving Pioneer Investment Management, Inc ("PIM"), the audit committee and
the independent auditors.

The Funds recognize that a Fund's independent auditors: 1) possess knowledge of
the Funds, 2) are able to incorporate certain services into the scope of the
audit, thereby avoiding redundant work, cost and disruption of Fund personnel
and processes, and 3) have expertise that has value to the Funds. As a result,
there are situations where it is desirable to use the Fund's independent
auditors for services in addition to the annual audit and where the potential
for conflicts of interests are minimal. Consequently, this policy, which is
intended to comply with Rule 210.2-01(C)(7), sets forth guidelines and
procedures to be followed by the Funds when retaining the independent audit firm
to perform audit, audit-related tax and other services under those
circumstances, while also maintaining independence.

Approval of a service in accordance with this policy for a Fund shall also
constitute approval for any other Fund whose pre-approval is required pursuant
to Rule 210.2-01(c)(7)(ii).

In addition to the procedures set forth in this policy, any non-audit services
that may be provided consistently with Rule 210.2-01 may be approved by the
Audit Committee itself and any pre-approval that may be waived in accordance
with Rule 210.2-01(c)(7)(i)(C) is hereby waived.

Selection of a Fund's independent auditors and their compensation shall be
determined by the Audit Committee and shall not be subject to this policy.



                               SECTION II - POLICY

---------------- -------------------------------- -------------------------------------------------
SERVICE           SERVICE CATEGORY DESCRIPTION      SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
CATEGORY
---------------- -------------------------------- -------------------------------------------------
                                            
I.  AUDIT        Services that are directly       o Accounting research assistance
SERVICES         related to performing the        o SEC consultation, registration
                 independent audit of the Funds     statements, and reporting
                                                  o Tax accrual related matters
                                                  o Implementation of new accounting
                                                    standards
                                                  o Compliance letters (e.g. rating agency
                                                    letters)
                                                  o Regulatory reviews and assistance
                                                    regarding financial matters
                                                  o Semi-annual reviews (if requested)
                                                  o Comfort letters for closed end
                                                    offerings
---------------- -------------------------------- -------------------------------------------------
II.              Services which are not           o AICPA attest and agreed-upon procedures
AUDIT-RELATED    prohibited under Rule            o Technology control assessments
SERVICES         210.2-01(C)(4) (the "Rule")      o Financial reporting control assessments
                 and are related extensions of    o Enterprise security architecture
                 the audit services support the     assessment
                 audit, or use the
                 knowledge/expertise gained
                 from the audit procedures as a
                 foundation to complete the
                 project.  In most cases, if
                 the Audit-Related Services are
                 not performed by the Audit
                 firm, the scope of the Audit
                 Services would likely
                 increase.  The Services are
                 typically well-defined and
                 governed by accounting
                 professional standards (AICPA,
                 SEC, etc.)
---------------- -------------------------------- -------------------------------------------------

 ------------------------------------- ------------------------------------
                                    
   AUDIT COMMITTEE APPROVAL POLICY               AUDIT COMMITTEE
                                                REPORTING POLICY
 ------------------------------------- ------------------------------------
                                    
 o "One-time" pre-approval             o A summary of all such
   for the audit period for all          services and related fees
   pre-approved specific service         reported at each regularly
   subcategories.  Approval of the       scheduled Audit Committee
   independent auditors as               meeting.
   auditors for a Fund shall
   constitute pre approval for
   these services.
 ------------------------------------- ------------------------------------
 o "One-time" pre-approval             o A summary of all such
   for the fund fiscal year within       services and related fees
   a specified dollar limit              (including comparison to
   for all pre-approved                  specified dollar limits)
   specific service subcategories        reported quarterly.

 o Specific approval is
   needed to exceed the
   pre-approved dollar limit for
   these services (see general
   Audit Committee approval policy
   below for details on obtaining
   specific approvals)

 o Specific approval is
   needed to use the Fund's
   auditors for Audit-Related
   Services not denoted as
   "pre-approved", or
   to add a specific service
   subcategory as "pre-approved"
 ------------------------------------- ------------------------------------




                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- --------------------------- -----------------------------------------------
   SERVICE CATEGORY          SERVICE CATEGORY        SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
                               DESCRIPTION
----------------------- --------------------------- -----------------------------------------------
                                              
III. TAX SERVICES       Services which are not      o Tax planning and support
                        prohibited by the Rule,     o Tax controversy assistance
                        if an officer of the Fund   o Tax compliance, tax returns, excise
                        determines that using the     tax returns and support
                        Fund's auditor to provide   o Tax opinions
                        these services creates
                        significant synergy in
                        the form of efficiency,
                        minimized disruption, or
                        the ability to maintain a
                        desired level of
                        confidentiality.
----------------------- --------------------------- -----------------------------------------------

------------------------------------- -------------------------
  AUDIT COMMITTEE APPROVAL POLICY         AUDIT COMMITTEE
                                          REPORTING POLICY
------------------------------------- -------------------------
------------------------------------- -------------------------
o "One-time" pre-approval             o A summary of
  for the fund fiscal  year             all such services and
  within a specified dollar limit       related fees
  				        (including comparison
  			                to specified dollar
  			                limits) reported
  			                quarterly.

o Specific approval is
  needed to exceed the
  pre-approved dollar limits for
  these services (see general
  Audit Committee approval policy
  below for details on obtaining
  specific approvals)

o Specific approval is
  needed to use the Fund's
  auditors for tax services not
  denoted as pre-approved, or to add a specific
  service subcategory as
  "pre-approved"
------------------------------------- -------------------------




                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- --------------------------- -----------------------------------------------
   SERVICE CATEGORY          SERVICE CATEGORY        SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
                               DESCRIPTION
----------------------- --------------------------- -----------------------------------------------
                                              
IV.  OTHER SERVICES     Services which are not      o Business Risk Management support
                        prohibited by the Rule,     o Other control and regulatory
A. SYNERGISTIC,         if an officer of the Fund     compliance projects
UNIQUE QUALIFICATIONS   determines that using the
                        Fund's auditor to provide
                        these services creates
                        significant synergy in
                        the form of efficiency,
                        minimized disruption,
                        the ability to maintain a
                        desired level of
                        confidentiality, or where
                        the Fund's auditors
                        posses unique or superior
                        qualifications to provide
                        these services, resulting
                        in superior value and
                        results for the Fund.
----------------------- --------------------------- -----------------------------------------------

--------------------------------------- ------------------------
    AUDIT COMMITTEE APPROVAL POLICY         AUDIT COMMITTEE
                                            REPORTING POLICY
------------------------------------- --------------------------
                                   
o "One-time" pre-approval             o A summary of
  for the fund fiscal year within       all such services and
  a specified dollar limit              related fees
  			               (including comparison
  			                to specified dollar
  				        limits) reported
                                        quarterly.
o Specific approval is
  needed to exceed the
  pre-approved dollar limits for
  these services (see general
  Audit Committee approval policy
  below for details on obtaining
  specific approvals)

o Specific approval is
  needed to use the Fund's
  auditors for "Synergistic" or
  "Unique Qualifications" Other
  Services not denoted as
  pre-approved to the left, or to
  add a specific service
  subcategory as "pre-approved"
------------------------------------- --------------------------




                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- ------------------------- -----------------------------------------------
   SERVICE CATEGORY         SERVICE CATEGORY        SPECIFIC PROHIBITED SERVICE SUBCATEGORIES
                              DESCRIPTION
----------------------- ------------------------- -----------------------------------------------
                                            
PROHIBITED  SERVICES    Services which result     1. Bookkeeping or other services
                        in the auditors losing       related to the accounting records or
                        independence status          financial statements of the audit
                        under the Rule.              client*
                                                  2. Financial information systems design
                                                     and implementation*
                                                  3. Appraisal or valuation services,
                                                     fairness* opinions, or
                                                     contribution-in-kind reports
                                                  4. Actuarial services (i.e., setting
                                                     actuarial reserves versus actuarial
                                                     audit work)*
                                                  5. Internal audit outsourcing services*
                                                  6. Management functions or human
                                                     resources
                                                  7. Broker or dealer, investment
                                                     advisor, or investment banking services
                                                  8. Legal services and expert services
                                                     unrelated to the audit
                                                  9. Any other service that the Public
                                                     Company Accounting Oversight Board
                                                     determines, by regulation, is
                                                     impermissible
----------------------- ------------------------- -----------------------------------------------

------------------------------------------- ------------------------------
     AUDIT COMMITTEE APPROVAL POLICY               AUDIT COMMITTEE
                                                  REPORTING POLICY
------------------------------------------- ------------------------------
o These services are not to be              o A summary of all
  performed with the exception of the(*)      services and related
  services that may be permitted              fees reported at each
  if they would not be subject to audit       regularly scheduled
  procedures at the audit client (as          Audit Committee meeting
  defined in rule 2-01(f)(4)) level           will serve as continual
  the firm providing the service.             confirmation that has
  				              not provided any
                                              restricted services.
------------------------------------------- ------------------------------

--------------------------------------------------------------------------------
GENERAL AUDIT COMMITTEE APPROVAL POLICY:
o For all projects, the officers of the Funds and the Fund's auditors will each
  make an assessment to determine that any proposed projects will not impair
  independence.

o Potential services will be classified into the four non-restricted service
  categories and the "Approval of Audit, Audit-Related, Tax and Other
  Services" Policy above will be applied. Any services outside the specific
  pre-approved service subcategories set forth above must be specifically
  approved by the Audit Committee.

o At least quarterly, the Audit Committee shall review a report summarizing the
  services by service category, including fees, provided by the Audit firm as
  set forth in the above policy.

--------------------------------------------------------------------------------


    (2) Disclose the percentage of services described in each of paragraphs (b)
   through (d) of this Item that were approved by the audit committee pursuant
   to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X.

Non-Audit Services
Beginning with non-audit service contracts entered
into on or after May 6, 2003, the effective date of the
new SEC pre-approval rules, the Trust's audit
committee is required to pre-approve services to
affiliates defined by SEC rules to the extent that the
services are determined to have a direct impact on the
operations or financial reporting of the Trust.  For the
years ended April 30 2017 and 2016, there were no
services provided to an affiliate that required the
Trust's audit committee pre-approval.



(f) If greater than 50 percent, disclose the percentage of hours expended on the
principal accountants engagement to audit the registrant's financial statements
for the most recent fiscal year that were attributed to work performed by
persons other than the principal accountant's full-time, permanent employees.

N/A

(g) Disclose the aggregate non-audit fees billed by the registrants accountant
for services rendered to the registrant, and rendered to the registrants
investment adviser (not including any sub-adviser whose role is primarily
portfolio management and is subcontracted with or overseen by another investment
adviser), and any entity controlling, controlled by, or under common control
with the adviser that provides ongoing services to the registrant for each of
the last two fiscal years of the registrant.

The aggregate non-audit fees for the Trust were $9,904
payable to Deloitte & Touche LLP for the year ended
April 30, 2017 and $9,876 for the year ended April 30, 2016.


(h) Disclose whether the registrants audit committee of the board of trustees
has considered whether the provision of non-audit services that were rendered to
the registrants investment adviser (not including any subadviser whose role is
primarily portfolio management and is subcontracted with or overseen by another
investment adviser), and any entity controlling, controlled by, or under common
control with the investment adviser that provides ongoing services to the
registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of
Rule 2-01 of Regulation S-X is compatible with maintaining the principal
accountant's independence.

The Fund's audit committee of the Board of Trustees
has considered whether the provision of non-audit
services that were rendered to the Affiliates (as
defined) that were not pre- approved pursuant to
paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is
compatible with maintaining the principal accountant's
independence.

ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS

(a) If the registrant is a listed issuer as defined in Rule 10A-3
under the Exchange Act (17 CFR 240.10A-3), state whether
or not the registrant has a separately-designated standing
 audit committee established in accordance with Section
3(a)(58)(A) of the Exchange Act (15 U.S.C. 78c(a)(58)(A)).
If the registrant has such a committee, however designated,
identify each committee member. If the entire board of directors
is acting as the registrant's audit committee as specified in
Section 3(a)(58)(B) of the Exchange Act (15 U.S.C. 78c(a)(58)(B)),
so state.

N/A

(b) If applicable, provide the disclosure required by Rule 10A-3(d)
under the Exchange Act (17 CFR 240.10A-3(d)) regarding an exemption
from the listing standards for audit committees.

N/A

ITEM 6. SCHEDULE OF INVESTMENTS.

File Schedule of Investments in securities of unaffiliated issuers
as of the close of the reporting period as set forth in 210.1212
of Regulation S-X [17 CFR 210.12-12], unless the schedule is
included as part of the report to shareholders filed under Item
1 of this Form.

Included in Item 1


ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR
CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

A closed-end management investment company that is filing an annual report on
this Form N-CSR must, unless it invests exclusively in non-voting securities,
describe the policies and procedures that it uses to determine how to vote
proxies relating to portfolio securities, including the procedures that the
company uses when a vote presents a conflict between the interests of its
shareholders, on the one hand, and those of the company's investment adviser;
principal underwriter; or any affiliated person (as defined in Section 2(a)(3)
of the Investment Company Act of 1940 (15 U.S.C. 80a-2(a)(3)) and the rules
thereunder) of the company, its investment adviser, or its principal
underwriter, on the other. Include any policies and procedures of the company's
investment adviser, or any other third party, that the company uses, or that are
used on the company's behalf, to determine how to vote proxies relating to
portfolio securities.

                     Proxy Voting Policies and Procedures of
                       Pioneer Investment Management, Inc.

                            VERSION DATED July, 2004

                                    Overview

   Pioneer Investment Management, Inc. ("Pioneer") is a fiduciary that owes
   each of its client's duties of care and loyalty with respect to all
   services undertaken on the client's behalf, including proxy voting. When
   Pioneer has been delegated proxy-voting authority for a client, the duty of
   care requires Pioneer to monitor corporate events and to vote the proxies.
   To satisfy its duty of loyalty, Pioneer must place its client's interests
   ahead of its own and must cast proxy votes in a manner consistent with the
   best interest of its clients. Pioneer will vote all proxies presented in a
   timely manner.

   The Proxy Voting Policies and Procedures are designed to complement
   Pioneer's investment policies and procedures regarding its general
   responsibility to monitor the performance and/or corporate events of
   companies that are issuers of securities held in accounts managed by
   Pioneer. Pioneer's Proxy Voting Policies summarize Pioneer's position on a
   number of issues solicited by companies held by Pioneer's clients. The
   policies are guidelines that provide a general indication on how Pioneer
   would vote but do not include all potential voting scenarios.

   Pioneer's Proxy Voting Procedures detail monitoring of voting, exception
   votes, and review of conflicts of interest and ensure that case-by-case
   votes are handled within the context of the overall guidelines (i.e. best
   interest of client). The overriding goal is that all proxies for US and
   non-US companies that are received promptly will be voted in accordance
   with Pioneer's policies or specific client instructions. All shares in a
   company held by Pioneer-managed accounts will be voted alike, unless a
   client has given us specific voting instructions on an issue or has not
   delegated authority to us or the Proxy Voting Oversight Group determines
   that the circumstances justify a different approach.

   Pioneer does not delegate the authority to vote proxies relating to its
   clients to any of its affiliates, which include other subsidiaries of
   UniCredito.

   Any questions about these policies and procedures should be directed to the
   Proxy Coordinator.

                                       1


                             Proxy Voting Procedures

   Proxy Voting Service
   Pioneer has engaged an independent proxy voting service to assist in the
   voting of proxies. The proxy voting service works with custodians to ensure
   that all proxy materials are received by the custodians and are processed
   in a timely fashion. To the extent applicable, the proxy voting service
   votes all proxies in accordance with the proxy voting policies established
   by Pioneer. The proxy voting service will refer proxy questions to the
   Proxy Coordinator (described below) for instructions under circumstances
   where: (1) the application of the proxy voting guidelines is unclear; (2) a
   particular proxy question is not covered by the guidelines; or (3) the
   guidelines call for specific instructions on a case-by-case basis. The
   proxy voting service is also requested to call to the Proxy Coordinator's
   attention specific proxy questions that, while governed by a guideline,
   appear to involve unusual or controversial issues. Pioneer reserves the
   right to attend a meeting in person and may do so when it determines that
   the company or the matters to be voted on at the meeting are strategically
   important to its clients.

   Proxy Coordinator
   Pioneer's Director of Investment Operations (the "Proxy Coordinator")
   coordinates the voting, procedures and reporting of proxies on behalf of
   Pioneer's clients. The Proxy Coordinator will deal directly with the proxy
   voting service and, in the case of proxy questions referred by the proxy
   voting service, will solicit voting recommendations and instructions from
   the Director of Portfolio Management US or, to the extent applicable,
   investment sub-advisers. The Proxy Coordinator is responsible for ensuring
   that these questions and referrals are responded to in a timely fashion and
   for transmitting appropriate voting instructions to the proxy voting
   service. The Proxy Coordinator is responsible for verifying with the
   Compliance Department whether Pioneer's voting power is subject to any
   limitations or guidelines issued by the client (or in the case of an
   employee benefit plan, the plan's trustee or other fiduciaries).

   Referral Items
   From time to time, the proxy voting service will refer proxy questions to
   the Proxy Coordinator that are described by Pioneer's policy as to be voted
   on a case-by-case basis, that are not covered by Pioneer's guidelines or
   where Pioneer's guidelines may be unclear with respect to the matter to be
   voted on. Under such certain circumstances, the Proxy Coordinator will seek
   a written voting recommendation from the Director of Portfolio Management
   US. Any such recommendation will include: (i) the manner in which the
   proxies should be voted; (ii) the rationale underlying any such decision;
   and (iii) the disclosure of any contacts or communications made between
   Pioneer and any outside parties concerning the proxy proposal prior to the
   time that the voting instructions are provided. In addition, the Proxy
   Coordinator will ask the Compliance Department to review the question for
   any actual or apparent conflicts of interest as described below under
   "Conflicts of

                                       2


   Interest." The Compliance Department will provide a "Conflicts of Interest
   Report," applying the criteria set forth below under "Conflicts of
   Interest," to the Proxy Coordinator summarizing the results of its review.
   In the absence of a conflict of interest, the Proxy Coordinator will vote
   in accordance with the recommendation of the Director of Portfolio
   Management US.

   If the matter presents a conflict of interest for Pioneer, then the Proxy
   Coordinator will refer the matter to the Proxy Voting Oversight Group for a
   decision. In general, when a conflict of interest is present, Pioneer will
   vote according to the recommendation of the Director of Portfolio
   Management US where such recommendation would go against Pioneer's interest
   or where the conflict is deemed to be immaterial. Pioneer will vote
   according to the recommendation of its proxy voting service when the
   conflict is deemed to be material and the Pioneer's internal vote
   recommendation would favor Pioneer's interest, unless a client specifically
   requests Pioneer to do otherwise. When making the final determination as to
   how to vote a proxy, the Proxy Voting Oversight Group will review the
   report from the Director of Portfolio Management US and the Conflicts of
   Interest Report issued by the Compliance Department.

   Conflicts of Interest
   A conflict of interest occurs when Pioneer's interests interfere, or appear
   to interfere with the interests of Pioneer's clients. Occasionally, Pioneer
   may have a conflict that can affect how its votes proxies. The conflict may
   be actual or perceived and may exist when the matter to be voted on
   concerns:

       o      An affiliate of Pioneer,  such as another company  belonging to
              the UniCredito  Italiano  S.p.A.  banking group (a "UniCredito
              Affiliate");

       o      An issuer of a security for which Pioneer acts as a sponsor,
              advisor, manager, custodian, distributor, underwriter, broker, or
              other similar capacity (including those securities specifically
              declared by PGAM to present a conflict of interest for Pioneer);

       o      An issuer of a security for which UniCredito has informed Pioneer
              that a UniCredito Affiliate acts as a sponsor, advisor, manager,
              custodian, distributor, underwriter, broker, or other similar
              capacity; or

       o      A person with whom Pioneer (or any of its affiliates) has an
              existing, material contract or business relationship that was not
              entered into in the ordinary course of Pioneer's business.

       o      Pioneer will abstain from voting with respect to companies
              directly or indirectly owned by UniCredito Italiano Group, unless
              otherwise directed by a client. In addition, Pioneer will inform
              PGAM Global Compliance and the PGAM Independent Directors before
              exercising such rights.

   Any associate involved in the proxy voting process with knowledge of any
   apparent or actual conflict of interest must disclose such conflict to the
   Proxy Coordinator and the Compliance Department. The Compliance Department
   will review each item referred to Pioneer to determine whether an actual or
   potential conflict of interest with Pioneer exists in connection with the
   proposal(s) to be voted upon. The review will be conducted by comparing the
   apparent parties affected by the proxy proposal being

                                       3


   voted upon against the Compliance Department's internal list of interested
   persons and, for any matches found, evaluating the anticipated magnitude
   and possible probability of any conflict of interest being present. For
   each referral item, the determination regarding the presence or absence of
   any actual or potential conflict of interest will be documented in a
   Conflicts of Interest Report to the Proxy Coordinator.

   Securities Lending
   In conjunction with industry standards Proxies are not available to be
   voted when the shares are out on loan through either Pioneer's lending
   program or a client's managed security lending program. However, Pioneer
   will reserve the right to recall lent securities so that they may be voted
   according to the Pioneer's instructions. If a portfolio manager would like
   to vote a block of previously lent shares, the Proxy Coordinator will work
   with the portfolio manager and Investment Operations to recall the
   security, to the extent possible, to facilitate the vote on the entire
   block of shares.

   Share-Blocking

   "Share-blocking" is a market practice whereby shares are sent to a
   custodian (which may be different than the account custodian) for record
   keeping and voting at the general meeting. The shares are unavailable for
   sale or delivery until the end of the blocking period (typically the day
   after general meeting date).

   Pioneer will vote in those countries with "share-blocking." In the event a
   manager would like to sell a security with "share-blocking", the Proxy
   Coordinator will work with the Portfolio Manager and Investment Operations
   Department to recall the shares (as allowable within the market time-frame
   and practices) and/or communicate with executing brokerage firm. A list of
   countries with "share-blocking" is available from the Investment Operations
   Department upon request.

   Record Keeping
   The Proxy Coordinator shall ensure that Pioneer's proxy voting service:

       o   Retains a copy of the proxy statement received (unless the proxy
           statement is available from the SEC's Electronic Data Gathering,
           Analysis, and Retrieval (EDGAR) system);

       o   Retains a record of the vote cast;

       o   Prepares Form N-PX for filing on behalf of each client that is a
           registered investment company; and

       o   Is able to promptly provide Pioneer with a copy of the voting
           record upon its request.

                                       4


   The Proxy Coordinator shall ensure that for those votes that may require
   additional documentation (i.e. conflicts of interest, exception votes and
   case-by-case votes) the following records are maintained:

       o    A record memorializing the basis for each referral vote cast;

       o    A copy of any document created by Pioneer that was material in
            making the decision on how to vote the subject proxy; and

       o    A copy of any conflict notice, conflict consent or any other
            written communication (including emails or other electronic
            communications) to or from the client (or in the case of an
            employee benefit plan, the plan's trustee or other fiduciaries)
            regarding the subject proxy vote cast by, or the vote
            recommendation of, Pioneer.

       o    Pioneer shall maintain the above records in the client's file for a
            period not less than ten (10) years.

     Disclosure
     Pioneer shall take reasonable measures to inform its clients of the process
     or procedures clients must follow to obtain information regarding how
     Pioneer voted with respect to assets held in their accounts. In addition,
     Pioneer shall describe to clients its proxy voting policies and procedures
     and will furnish a copy of its proxy voting policies and procedures upon
     request. This information may be provided to clients through Pioneer's Form
     ADV (Part II) disclosure, by separate notice to the client, or through
     Pioneer's website.

     Proxy Voting Oversight Group
     The members of the Proxy Voting Oversight Group are Pioneer's: Director of
     Portfolio Management US, Head of Investment Operations, and Director of
     Compliance. Other members of Pioneer will be invited to attend meetings and
     otherwise participate as necessary. The Head of Investment Operations will
     chair the Proxy Voting Oversight Group.

     The Proxy Voting Oversight Group is responsible for developing, evaluating,
     and changing (when necessary) Pioneer's Proxy Voting Policies and
     Procedures. The group meets at least annually to evaluate and review these
     policies and procedures and the services of its third-party proxy voting
     service. In addition, the Proxy Voting Oversight Group will meet as
     necessary to vote on referral items and address other business as
     necessary.

     Amendments
     Pioneer may not amend its Proxy Voting Policies And Procedures without the
     prior approval of the Proxy Voting Oversight Group and its corporate
     parent, Pioneer Global Asset Management S.p.A

                                       5


   Proxy Voting Policies
   Pioneer's sole concern in voting proxies is the economic effect of the
   proposal on the value of portfolio holdings, considering both the short-
   and long-term impact. In many instances, Pioneer believes that supporting
   the company's strategy and voting "for" management's proposals builds
   portfolio value. In other cases, however, proposals set forth by management
   may have a negative effect on that value, while some shareholder proposals
   may hold the best prospects for enhancing it. Pioneer monitors developments
   in the proxy-voting arena and will revise this policy as needed.

   All proxies that are received promptly will be voted in accordance with the
   specific policies listed below. All shares in a company held by
   Pioneer-managed accounts will be voted alike, unless a client has given us
   specific voting instructions on an issue or has not delegated authority to
   us. Proxy voting issues will be reviewed by Pioneer's Proxy Voting
   Oversight Group, which consists of the Director of Portfolio Management US,
   the Director of Investment Operations (the Proxy Coordinator), and the
   Director of Compliance.

   Pioneer has established Proxy Voting Procedures for identifying and
   reviewing conflicts of interest that may arise in the voting of proxies.

   Clients may request, at any time, a report on proxy votes for securities
   held in their portfolios and Pioneer is happy to discuss our proxy votes
   with company management. Pioneer retains a proxy voting service to provide
   research on proxy issues and to process proxy votes.

Administrative
   While administrative items appear infrequently in U.S. issuer proxies, they
   are quite common in non-U.S. proxies.

   We will generally support these and similar management proposals:

       o    Corporate name change.

       o    A change of corporate headquarters.

       o    Stock exchange listing.

       o    Establishment of time and place of annual meeting.

       o    Adjournment or postponement of annual meeting.

       o    Acceptance/approval of financial statements.

       o    Approval of dividend payments, dividend reinvestment plans and other
            dividend-related proposals.

       o    Approval of minutes and other formalities.

                                       6


       o    Authorization of the transferring of reserves and allocation of
            income.

       o    Amendments to authorized signatories.

       o    Approval of accounting method changes or change in fiscal year-end.

       o    Acceptance of labor agreements.

       o    Appointment of internal auditors.

   Pioneer will vote on a case-by-case basis on other routine business;
   however, Pioneer will oppose any routine business proposal if insufficient
   information is presented in advance to allow Pioneer to judge the merit of
   the proposal. Pioneer has also instructed its proxy voting service to
   inform Pioneer of its analysis of any administrative items inconsistent, in
   its view, with supporting the value of Pioneer portfolio holdings so that
   Pioneer may consider and vote on those items on a case-by-case basis.

Auditors
     We normally vote for proposals to:

       o    Ratify the auditors. We will consider a vote against if we are
            concerned about the auditors' independence or their past work for
            the company. Specifically, we will oppose the ratification of
            auditors and withhold votes from audit committee members if
            non-audit fees paid by the company to the auditing firm exceed the
            sum of audit fees plus audit-related fees plus permissible tax
            fees according to the disclosure categories proposed by the
            Securities and Exchange Commission.

       o    Restore shareholder rights to ratify the auditors.

     We will normally oppose proposals that require companies to:

       o    Seek bids from other auditors.

       o    Rotate auditing firms, except where the rotation is statutorily
            required or where rotation would demonstrably strengthen financial
            disclosure.

       o    Indemnify auditors.

       o    Prohibit auditors from engaging in non-audit services for the
            company.

     Board of Directors
     On issues related to the board of directors, Pioneer normally supports
     management. We will, however, consider a vote against management in
     instances where corporate performance has been very poor or where the board
     appears to lack independence.

                                       7


     General Board Issues
     Pioneer will vote for:

       o    Audit, compensation and nominating committees composed of
            independent directors exclusively.

       o    Indemnification for directors for actions taken in good faith in
            accordance with the business judgment rule. We will vote against
            proposals for broader indemnification.

       o    Changes in board size that appear to have a legitimate business
            purpose and are not primarily for anti-takeover reasons.

       o    Election of an honorary director.

     We will vote against:

       o    Minimum stock ownership by directors.

       o    Term limits for directors. Companies benefit from experienced
            directors, and shareholder control is better achieved through
            annual votes.

       o    Requirements for union or special interest representation on the
            board.

       o    Requirements to provide two candidates for each board seat.

     We will vote on a case-by case basis on these issues:

       o    Separate chairman and CEO positions. We will consider voting with
            shareholders on these issues in cases of poor corporate
            performance.

     Elections of Directors
     In uncontested elections of directors we will vote against:

       o    Individual directors with absenteeism above 25% without valid
            reason. We support proposals that require disclosure of director
            attendance.

       o    Insider directors and affiliated outsiders who sit on the audit,
            compensation, stock option or nominating committees. For the
            purposes of our policy, we accept the definition of affiliated
            directors provided by our proxy voting service.

     We will also vote against:

       o    Directors who have failed to act on a takeover offer where the
            majority of shareholders have tendered their shares.

       o    Directors who appear to lack independence or are associated with
            very poor corporate performance.

                                       8


     We will vote on a case-by case basis on these issues:

       o    Re-election of directors who have implemented or renewed a
            dead-hand or modified dead-hand poison pill (a "dead-hand poison
            pill" is a shareholder rights plan that may be altered only by
            incumbent or "dead " directors. These plans prevent a potential
            acquirer from disabling a poison pill by obtaining control of the
            board through a proxy vote).

       o    Contested election of directors.

       o    Prior to phase-in required by SEC, we would consider supporting
            election of a majority of independent directors in cases of poor
            performance.

       o    Mandatory retirement policies.

       o    Directors who have ignored a shareholder proposal that has been
            approved by shareholders for two consecutive years.

     Takeover-Related Measures
     Pioneer is generally opposed to proposals that may discourage takeover
     attempts. We believe that the potential for a takeover helps ensure that
     corporate performance remains high.

     Pioneer will vote for:

       o    Cumulative voting.

       o    Increase ability for shareholders to call special meetings.

       o    Increase ability for shareholders to act by written consent.

       o    Restrictions on the ability to make greenmail payments.

       o    Submitting rights plans to shareholder vote.

       o    Rescinding shareholder rights plans ("poison pills").

       o    Opting out of the following state takeover statutes:

     o Control share acquisition statutes, which deny large holders voting
       rights on holdings over a specified threshold.

     o Control share cash-out provisions, which require large holders to
       acquire shares from other holders.

     o Freeze-out provisions, which impose a waiting period on large
       holders before they can attempt to gain control.

     o Stakeholder laws, which permit directors to consider interests of
       non-shareholder constituencies.

                                       9


     o Disgorgement provisions, which require acquirers to disgorge profits
       on purchases made before gaining control.

     o Fair price provisions.

     o Authorization of shareholder rights plans.

     o Labor protection provisions.

     o Mandatory classified boards.

     We will vote on a case-by-case basis on the following issues:

       o    Fair price provisions. We will vote against provisions requiring
            supermajority votes to approve takeovers. We will also consider
            voting against proposals that require a supermajority vote to
            repeal or amend the provision. Finally, we will consider the
            mechanism used to determine the fair price; we are generally
            opposed to complicated formulas or requirements to pay a premium.

       o    Opting out of state takeover statutes regarding fair price
            provisions. We will use the criteria used for fair price
            provisions in general to determine our vote on this issue.

       o    Proposals that allow shareholders to nominate directors.

     We will vote against:

       o    Classified boards, except in the case of closed-end mutual funds.

       o    Limiting shareholder ability to remove or appoint directors. We
            will support proposals to restore shareholder authority in this
            area. We will review on a case-by-case basis proposals that
            authorize the board to make interim appointments.

       o    Classes of shares with unequal voting rights.

       o    Supermajority vote requirements.

       o    Severance packages ("golden" and "tin" parachutes). We will support
            proposals to put these packages to shareholder vote.

       o    Reimbursement of dissident proxy solicitation expenses. While we
            ordinarily support measures that encourage takeover bids, we
            believe that management should have full control over corporate
            funds.

       o    Extension of advance notice requirements for shareholder proposals.

       o    Granting board authority normally retained by shareholders (e.g.,
            amend charter, set board size).

       o    Shareholder rights plans ("poison pills"). These plans generally
            allow shareholders to buy additional shares at a below-market
            price in the event of a change in control and may deter some bids.

                                       10


     Capital Structure
     Managements need considerable flexibility in determining the company's
     financial structure, and Pioneer normally supports managements' proposals
     in this area. We will, however, reject proposals that impose high barriers
     to potential takeovers.

     Pioneer will vote for:

       o    Changes in par value.

       o    Reverse splits, if accompanied by a reduction in number of shares.

       o    Share repurchase programs, if all shareholders may participate on
            equal terms.

       o    Bond issuance.

       o    Increases in "ordinary" preferred stock.

       o    Proposals to have blank-check common stock placements (other than
            shares issued in the normal course of business) submitted for
            shareholder approval.

       o    Cancellation of company treasury shares.

     We will vote on a case-by-case basis on the following issues:

       o    Reverse splits not accompanied by a reduction in number of shares,
            considering the risk of delisting.

       o    Increase in authorized common stock. We will make a determination
            considering, among other factors:

     o Number of shares currently available for issuance;

     o Size of requested increase (we would normally approve increases of up to
       100% of current authorization);

     o Proposed use of the additional shares; and

     o Potential consequences of a failure to increase the number of shares
       outstanding (e.g., delisting or bankruptcy).

       o    Blank-check preferred. We will normally oppose issuance of a new
            class of blank-check preferred, but may approve an increase in a
            class already outstanding if the company has demonstrated that it
            uses this flexibility appropriately.

       o    Proposals to submit private placements to shareholder vote.

       o    Other financing plans.

     We will vote against preemptive rights that we believe limit a company's
financing flexibility.

                                      11


     Compensation
     Pioneer supports compensation plans that link pay to shareholder returns
     and believes that management has the best understanding of the level of
     compensation needed to attract and retain qualified people. At the same
     time, stock-related compensation plans have a significant economic impact
     and a direct effect on the balance sheet. Therefore, while we do not want
     to micromanage a company's compensation programs, we will place limits on
     the potential dilution these plans may impose.

     Pioneer will vote for:

       o    401(k) benefit plans.

       o    Employee stock ownership plans (ESOPs), as long as shares
            allocated to ESOPs are less than 5% of outstanding shares. Larger
            blocks of stock in ESOPs can serve as a takeover defense. We will
            support proposals to submit ESOPs to shareholder vote.

       o    Various issues related to the Omnibus Budget and Reconciliation Act
            of 1993 (OBRA), including:

     o Amendments to performance plans to conform with OBRA;

     o Caps on annual grants or amendments of administrative features;

     o Adding performance goals; and

     o Cash or cash-and-stock bonus plans.

       o    Establish a process to link pay, including stock-option grants, to
            performance, leaving specifics of implementation to the company.

       o    Require that option repricings be submitted to shareholders.

       o    Require the expensing of stock-option awards.

       o    Require reporting of executive retirement benefits (deferred
            compensation, split-dollar life insurance, SERPs, and pension
            benefits).

       o    Employee stock purchase plans where the purchase price is equal to
            at least 85% of the market price, where the offering period is no
            greater than 27 months and where potential dilution (as defined
            below) is no greater than 10%.

                                       12


     We will vote on a case-by-case basis on the following issues:

       o    Executive and director stock-related compensation plans. We will
            consider the following factors when reviewing these plans:

       o    The program must be of a reasonable size. We will approve plans
            where the combined employee and director plans together would
            generate less than 15% dilution. We will reject plans with 15% or
            more potential dilution.

            Dilution = (A + B + C) / (A + B + C + D), where

            A = Shares reserved for plan/amendment,

            B = Shares available under continuing plans,

            C = Shares granted but unexercised and

            D = Shares outstanding.

       o    The plan must not:

            o   Explicitly permit unlimited option repricing authority or that
                have repriced in the past without shareholder approval.

            o   Be a self-replenishing "evergreen" plan, plans that grant
                discount options and tax offset payments.

     o We are generally in favor of proposals that increase participation beyond
       executives.

     o We generally support proposals asking companies to adopt rigorous
       vesting provisions for stock option plans such as those that vest
       incrementally over, at least, a three- or four-year period with a pro
       rata portion of the shares becoming exercisable on an annual basis
       following grant date.

     o We generally support proposals asking companies to disclose their
       window period policies for stock transactions. Window period policies
       ensure that employees do not exercise options based on insider
       information contemporaneous with quarterly earnings releases and other
       material corporate announcements.

     o We generally support proposals asking companies to adopt stock holding
       periods for their executives.

       o    All other employee stock purchase plans.

       o    All other compensation-related proposals, including deferred
            compensation plans, employment agreements, loan guarantee programs
            and retirement plans.

       o    All other proposals regarding stock compensation plans, including
            extending the life of a plan, changing vesting restrictions,
            repricing options, lengthening exercise periods or accelerating
            distribution of awards and pyramiding and cashless exercise
            programs.

                                       13


     We will vote against:

       o    Pensions for non-employee directors. We believe these retirement
            plans reduce director objectivity.

       o    Elimination of stock option plans.

     We will vote on a case-by case basis on these issues:

       o    Limits on executive and director pay.

       o    Stock in lieu of cash compensation for directors.

     Corporate Governance
     Pioneer will vote for:

       o    Confidential Voting.

       o    Equal access provisions, which allow shareholders to contribute
            their opinion to proxy materials.

       o    Proposals requiring directors to disclose their ownership of shares
            in the company.

     We will vote on a case-by-case basis on the following issues:

       o    Change in the state of incorporation. We will support
            reincorporations supported by valid business reasons. We will
            oppose those that appear to be solely for the purpose of
            strengthening takeover defenses.

       o    Bundled proposals. We will evaluate the overall impact of the
            proposal.

       o    Adopting or amending the charter, bylaws or articles of association.

       o    Shareholder appraisal rights, which allow shareholders to demand
            judicial review of an acquisition price.

     We will vote against:

       o    Shareholder advisory committees. While management should solicit
            shareholder input, we prefer to leave the method of doing so to
            management's discretion.

       o    Limitations on stock ownership or voting rights.

       o    Reduction in share ownership disclosure guidelines.

                                       14


     Mergers and Restructurings
     Pioneer will vote on the following and similar issues on a case-by-case
     basis:

       o    Mergers and acquisitions.

       o    Corporate restructurings, including spin-offs, liquidations, asset
            sales, joint ventures, conversions to holding company and
            conversions to self-managed REIT structure.

       o    Debt restructurings.

       o    Conversion of securities.

       o    Issuance of shares to facilitate a merger.

       o    Private placements, warrants, convertible debentures.

       o    Proposals requiring management to inform shareholders of merger
            opportunities.

     We will normally vote against shareholder proposals requiring that the
     company be put up for sale.

     Mutual Funds
     Many of our portfolios may invest in shares of closed-end mutual funds or
     exchange-traded funds. The non-corporate structure of these investments
     raises several unique proxy voting issues.

     Pioneer will vote for:

       o    Establishment of new classes or series of shares.

       o    Establishment of a master-feeder structure.

     Pioneer will vote on a case-by-case on:

       o    Changes in investment policy. We will normally support changes
            that do not affect the investment objective or overall risk level
            of the fund. We will examine more fundamental changes on a
            case-by-case basis.

       o    Approval of new or amended advisory contracts.

       o    Changes from closed-end to open-end format.

       o    Authorization for, or increase in, preferred shares.

       o    Disposition of assets, termination, liquidation, or mergers.

       o    Classified boards of closed-end mutual funds, but will typically
            support such proposals.

                                       15


     Social Issues
     Pioneer will abstain on stockholder proposals calling for greater
     disclosure of corporate activities with regard to social issues. "Social
     Issues" may generally be described as shareholder proposals for a company
     to:

       o    Conduct studies regarding certain issues of public concern and
            interest;

       o    Study the feasibility of the company taking certain actions with
            regard to such issues; or

       o    Take specific action, including ceasing certain behavior and
            adopting company standards and principles, in relation to issues
            of public concern and interest.

     We believe these issues are important and should receive management
     attention.

     Pioneer will vote against proposals calling for substantial changes in the
     company's business or activities. We will also normally vote against
     proposals with regard to contributions, believing that management should
     control the routine disbursement of funds.

                                       16




ITEM 8. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

(a) If the registrant is a closed-end management investment company that
is filing an annual report on this Form N-CSR,provide the following
information:
(1) State the name, title, and length of service of the person or persons
employed by or associated with the registrant or an investment adviser
of the registrant who are primarily responsible for the day-to-day management
of the registrant's portfolio ("Portfolio Manager"). Also state each Portfolio
Manager's business experience during the past 5 years.


ADDITIONAL INFORMATION ABOUT THE PORTFOLIO MANAGER

OTHER ACCOUNTS MANAGED BY THE PORTFOLIO MANAGER
The table below indicates, for the portfolio manager of the fund, information
about the accounts other than the fund over which the portfolio manager has
day-to-day investment responsibility. All information on the number of accounts
and total assets in the table is as of April 30, 2017. For purposes of the
table, "Other Pooled Investment Vehicles" may include investment partnerships,
undertakings for collective investments in transferable securities ("UCITS")
and other non-U.S. investment funds and group trusts, and "Other Accounts" may
include separate accounts for institutions or individuals, insurance company
general or separate accounts, pension funds and other similar institutional
accounts but generally do not include the portfolio manager's personal
investment accounts or those which the manager may be deemed to own
beneficially under the code of ethics. Certain funds and other accounts managed
by the portfolio manager may have substantially similar investment strategies.




                                                                                               NUMBER OF          ASSETS
                                                                                                ACCOUNTS         MANAGED
                                                                                             MANAGED FOR       FOR WHICH
                                                                                          WHICH ADVISORY        ADVISORY
                                                          NUMBER OF                               FEE IS          FEE IS
NAME OF                                                    ACCOUNTS       TOTAL ASSETS      PERFORMANCE-    PERFORMANCE-
PORTFOLIO MANAGER    TYPE OF ACCOUNT                        MANAGED    MANAGED (000'S)             BASED   BASED (000'S)
-------------------  ---------------------------------- -----------  -----------------  ----------------  --------------
                                                                                           
David Eurkus         Other Registered Investment
                     Companies                                  3    $2,230,015                      N/A             N/A
                     Other Pooled Investment Vehicles           0    $        0                      N/A             N/A
                     Other Accounts                             0    $        0                      N/A             N/A
-------------------  ---------------------------------- -----------  ----------         ----------------  --------------
Jonathan Chirunga    Other Registered
                     Investment Companies                       3    $2,230,015                      N/A             N/A
                     Other Pooled Investment Vehicles           0    $        0                      N/A             N/A
                     Other Accounts                             0    $        0                      N/A             N/A
-------------------  ---------------------------------- -----------  ----------         ----------------  --------------


POTENTIAL CONFLICTS OF INTEREST
When a portfolio manager is responsible for the management of more than one
account, the potential arises for the portfolio manager to favor one account
over another. The principal types of potential conflicts of interest that may
arise are discussed below. For the reasons outlined below, Pioneer does not
believe that any material conflicts are likely to arise out of a portfolio
manager's responsibility for the management of the fund as well as one or more
other accounts. Although Pioneer has adopted procedures that it believes are
reasonably designed to detect and prevent violations of the federal securities
laws and to mitigate the potential for conflicts of interest to affect its
portfolio management decisions, there can be no assurance that all conflicts
will be identified or that all procedures will be effective in mitigating the
potential for such risks. Generally, the risks of such conflicts of interest
are increased to the extent that a portfolio manager has a financial incentive
to favor one account over another. Pioneer has structured its compensation
arrangements in a manner that is intended to limit such potential for conflicts
of interest. See "Compensation of Portfolio Managers" below.

o A portfolio manager could favor one account over another in allocating new
  investment opportunities that have limited supply, such as initial public
  offerings and private placements. If, for example, an initial public
  offering that was expected to appreciate in value significantly shortly
  after the offering was allocated to a single account, that account may be
  expected to have better investment performance than other accounts that did
  not receive an allocation of the initial public offering. Generally,
  investments for which there is limited availability are allocated based upon
  a range of factors including available cash and


                                       0


 consistency with the accounts' investment objectives and policies. This
 allocation methodology necessarily involves some subjective elements but is
 intended over time to treat each client in an equitable and fair manner.
 Generally, the investment opportunity is allocated among participating
 accounts on a pro rata basis. Although Pioneer believes that its practices are
 reasonably designed to treat each client in an equitable and fair manner,
 there may be instances where a fund may not participate, or may participate to
 a lesser degree than other clients, in the allocation of an investment
 opportunity.

o A portfolio manager could favor one account over another in the order in
  which trades for the accounts are placed. If a portfolio manager determines
  to purchase a security for more than one account in an aggregate amount that
  may influence the market price of the security, accounts that purchased or
  sold the security first may receive a more favorable price than accounts
  that made subsequent transactions. The less liquid the market for the
  security or the greater the percentage that the proposed aggregate purchases
  or sales represent of average daily trading volume, the greater the
  potential for accounts that make subsequent purchases or sales to receive a
  less favorable price. When a portfolio manager intends to trade the same
  security on the same day for more than one account, the trades typically are
  "bunched," which means that the trades for the individual accounts are
  aggregated and each account receives the same price. There are some types of
  accounts as to which bunching may not be possible for contractual reasons
  (such as directed brokerage arrangements). Circumstances may also arise
  where the trader believes that bunching the orders may not result in the
  best possible price. Where those accounts or circumstances are involved,
  Pioneer will place the order in a manner intended to result in as favorable
  a price as possible for such client.

o A portfolio manager could favor an account if the portfolio manager's
  compensation is tied to the performance of that account to a greater degree
  than other accounts managed by the portfolio manager. If, for example, the
  portfolio manager receives a bonus based upon the performance of certain
  accounts relative to a benchmark while other accounts are disregarded for
  this purpose, the portfolio manager will have a financial incentive to seek
  to have the accounts that determine the portfolio manager's bonus achieve
  the best possible performance to the possible detriment of other accounts.
  Similarly, if Pioneer receives a performance-based advisory fee, the
  portfolio manager may favor that account, whether or not the performance of
  that account directly determines the portfolio manager's compensation.

o A portfolio manager could favor an account if the portfolio manager has a
  beneficial interest in the account, in order to benefit a large client or to
  compensate a client that had poor returns. For example, if the portfolio
  manager held an interest in an investment partnership that was one of the
  accounts managed by the portfolio manager, the portfolio manager would have
  an economic incentive to favor the account in which the portfolio manager
  held an interest.

o If the different accounts have materially and potentially conflicting
  investment objectives or strategies, a conflict of interest could arise. For
  example, if a portfolio manager purchases a security for one account and
  sells the same security for another account, such trading pattern may
  disadvantage either the account that is long or short. In making portfolio
  manager assignments, Pioneer seeks to avoid such potentially conflicting
  situations. However, where a portfolio manager is responsible for accounts
  with differing investment objectives and policies, it is possible that the
  portfolio manager will conclude that it is in the best interest of one
  account to sell a portfolio security while another account continues to hold
  or increase the holding in such security.


COMPENSATION OF PORTFOLIO MANAGER
Pioneer has adopted a system of compensation for portfolio managers that seeks
to align the financial interests of the portfolio managers with those of
shareholders of the accounts (including Pioneer funds) the portfolio managers
manage, as well as with the financial performance of Pioneer. The compensation
program for all Pioneer portfolio managers includes a base salary (determined
by the rank and tenure of the employee) and an annual bonus program, as well as
customary benefits that are offered generally to all full-time employees. Base
compensation is fixed and normally reevaluated on an annual basis. Pioneer
seeks to set base compensation at market rates, taking into account the
experience and responsibilities of


                                       1


the portfolio manager. The bonus plan is intended to provide a competitive
level of annual bonus compensation that is tied to the portfolio manager
achieving superior investment performance and align the interests of the
investment professional with those of shareholders, as well as with the
financial performance of Pioneer. Any bonus under the plan is completely
discretionary, with a maximum annual bonus that may be in excess of base
salary. The annual bonus is based upon a combination of the following factors:

o QUANTITATIVE INVESTMENT PERFORMANCE. The quantitative investment performance
  calculation is based on pre-tax investment performance of all of the
  accounts managed by the portfolio manager (which includes the fund and any
  other accounts managed by the portfolio manager) over a one-year period (20%
  weighting) and four-year period (80% weighting), measured for periods ending
  on December 31. The accounts, which include the fund, are ranked against a
  group of mutual funds with similar investment objectives and investment
  focus (60%) and a broad-based securities market index measuring the
  performance of the same type of securities in which the accounts invest
  (40%), which, in the case of the fund, is the Barclays Capital Municipal
  Bond Index and Barclays Capital High Yield Municipal Bond Index. As a result
  of these two benchmarks, the performance of the portfolio manager for
  compensation purposes is measured against the criteria that are relevant to
  the portfolio manager's competitive universe.

o QUALITATIVE PERFORMANCE. The qualitative performance component with respect
  to all of the accounts managed by the portfolio manager includes objectives,
  such as effectiveness in the areas of teamwork, leadership, communications
  and marketing, that are mutually established and evaluated by each portfolio
  manager and management.

o PIONEER RESULTS AND BUSINESS LINE RESULTS. Pioneer's financial performance,
  as well as the investment performance of its investment management group,
  affect a portfolio manager's actual bonus by a leverage factor of plus or
  minus (+/-) a predetermined percentage.

The quantitative and qualitative performance components comprise 80% and 20%,
respectively, of the overall bonus calculation (on a pre-adjustment basis). A
portion of the annual bonus is deferred for a specified period and may be
invested in one or more Pioneer funds.

Certain portfolio managers participate in other programs designed to reward and
retain key contributors. Senior executives or other key employees are granted
performance units based on the stock price performance of UniCredit and the
financial performance of Pioneer Global Asset Management S.p.A., which are
affiliates of Pioneer. Portfolio managers also may participate in a deferred
compensation program, whereby deferred amounts are invested in one or more
Pioneer funds.


SHARE OWNERSHIP BY PORTFOLIO MANAGERS
The following table indicates as of April 30, 2017 the value, within the
indicated range, of shares beneficially owned by the portfolio managers of the
fund.




                             BENEFICIAL OWNERSHIP
NAME OF PORTFOLIO MANAGER    OF THE FUND*
---------------------------  ---------------------
                          
David Eurkus                 A
---------------------------  ---------------------
Jonathan Chirunga            A
---------------------------  ---------------------


*     Key to Dollar Ranges


  
A.   None
B.   $1 - $10,000
C.   $10,001 - $50,000
D.   $50,001 - $100,000
E.   $100,001 - $500,000
F.   $500,001 - $1,000,000
G.   Over $1,000,000



                                       2



ITEM 9. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT
INVESTMENT COMPANY AND AFFILIATED PURCHASERS.

(a) If the registrant is a closed-end management investment company,
in the following tabular format, provide the information specified in
paragraph (b) of this Item with respect to any purchase made by or on
behalf of the registrant or any affiliated purchaser, as defined in
Rule 10b-18(a)(3) under the Exchange Act (17 CFR 240.10b-18(a)(3)), of
shares or other units of any class of the registrant's equity securities
that is registered by the registrant pursuant to Section 12 of the
Exchange Act (15 U.S.C. 781).

During the period covered by this report, there were no purchases
made by or on behalf of the registrant or any affiliated purchaser
as defined in Rule 10b-18(a)(3) under the Securities Exchange Act
of 1934 (the Exchange Act), of shares of the registrants equity
securities that are registered by the registrant pursuant to
Section 12 of the Exchange Act.


ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

Describe any material changes to the procedures by which shareholders
may recommend nominees to the registrant's board of directors, where
those changes were implemented after the registrant last provided
disclosure in response to the requirements of Item 407(c)(2)(iv) of
Regulation S-R(17 CFR 229.407)(as required by Item 22(b)(15))
of Schedule 14A (17 CFR 240.14a-101), or this Item.


There have been no material changes to the procedures by which the
shareholders may recommend nominees to the registrant's board of
directors since the registrant last provided disclosure in response
to the requirements of Item 407(c)(2)(iv) of Regulation S-R of Schedule 14(A)
in its definitive proxy statement, or this item.


ITEM 11. CONTROLS AND PROCEDURES.

(a) Disclose the conclusions of the registrant's principal executive and
principal financials officers, or persons performing similar functions,
regarding the effectiveness of the registrant's disclosure
controls and procedures (as defined in Rule 30a-3(c) under the Act (17 CFR
270.30a-3(c))) as of a date within 90 days of the filing date of the report
that includes the disclosure required by this paragraph,
based on the evaluation of these controls and procedures required by Rule
30a-3(b) under the Act (17 CFR 270.30(a)-3(b) and Rules 13a-15(b) or 15d-15(b)
under the Exchange Act (17 CFR 240.13a-15(b) or 240.15d-15(b)).

The registrant's principal executive officer
and principal financial officer have
concluded that the registrant's disclosure
controls and procedures are effective based
on the evaluation of these controls and
procedures as of a date within 90 days of the
filing date of this report.


(b) Disclose any change in the registrant's internal control over financial
reporting (as defined in Rule 30a-3(d) under the Act (17CFR 270.30a-3(d)) that
occured during the second fiscal quarter of the period covered by this report
that has materially affected, or is reasonably likely to materially affect,
the registrant's internal control over financial reporting.

There were no significant changes in the
registrant's internal control over financial
reporting that occurred during the second
fiscal quarter of the period covered by this
report that have materially affected, or are
reasonably likely to materially affect, the
registrant's internal control over financial
reporting.

The registrant's principal executive officer and principal financial
officer, however, voluntarily are reporting the following information:

In August of 2006 the registrant's investment adviser
enhanced its internal procedures for reporting performance
information required to be included in prospectuses.
Those enhancements involved additional internal controls
over the appropriateness of performance data
generated for this purpose.  Such enhancements were made
following an internal review which identified
prospectuses relating to certain classes of shares of
a limited number of registrants where, inadvertently,
performance information not reflecting the deduction of
applicable sales charges was included. Those prospectuses
were revised, and the revised prospectuses were distributed to
shareholders.


ITEM 12. EXHIBITS.

(a) File the exhibits listed below as part of this Form. Letter or number the
exhibits in the sequence indicated.

(1) Any code of ethics, or amendment thereto, that is the subject of the
disclosure required by Item 2, to the extent that the registrant intends to
satisfy the Item 2 requirements through filing of an exhibit.



(2) A separate certification for each principal executive officer and principal
financial officer of the registrant as required by Rule 30a-2(a) under the Act
(17 CFR 270.30a-2(a)) , exactly as set forth below:

Filed herewith.





                                   SIGNATURES

                          [See General Instruction F]


Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, the registrant has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.


(Registrant) Pioneer Municipal High Income Trust


By (Signature and Title)* /s/ Lisa M. Jones
Lisa M. Jones, President & Chief Executive Officer

Date June 27, 2017


Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, this report has been signed below by the
following persons on behalf of the registrant and in the capacities and on the
dates indicated.


By (Signature and Title)* /s/ Lisa M. Jones
Lisa M. Jones, President & Chief Executive Officer

Date June 27, 2017


By (Signature and Title)* /s/ Mark E. Bradley
Mark E. Bradley, Treasurer & Chief Accounting & Financial Officer

Date June 27, 2017

* Print the name and title of each signing officer under his or her signature.