FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Chang Daniel Kuang Ming   2. Issuer Name and Ticker or Trading Symbol ALPHA & OMEGA SEMICONDUCTOR Ltd [AOSL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Senior VP of Marketing (Last) (First) (Middle) 475 OAKMEAD PARKWAY 3. Date of Earliest Transaction (Month/Day/Year) 03/15/2018 (Street) SUNNYVALE, CA 94085 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Share 03/15/2018   M   2,250 (1) A $ 0 49,820 (2) D   Common Share 03/15/2018   F   746 (3) D $ 16.22 49,074 (2) D   Common Share 03/15/2018   F   4,715 (4) D $ 16.22 44,359 (2) D   Common Share 03/15/2018   A   8,000 (5) A $ 0 52,359 (2) D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Performance RSU

$ 0

03/15/2018

M

2,500 (6)

(6)

(6)

Common Share

2,500

$ 0

7,500

D

Performance RSU

$ 0

03/15/2018

A

13,000 (7)

(7)

(7)

Common Shares

13,000

$ 0

13,000

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Chang Daniel Kuang Ming 475 OAKMEAD PARKWAY SUNNYVALE, CA 94085			Senior VP of Marketing

Signatures

/s/ Yanbing Hong, attorney-in-fact for Daniel Kuang Ming Chang		03/19/2018
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Represents the actual number of common shares issued upon vesting of performance share units ("PSU") based on the level of achievement of specified performance goals set forth in the Reporting Person's PSU agreement.
(2)	Includes an aggregate of 32,642 shares subject to restricted share units (RSU) awards granted on March 16, 2015, March 15, 2016, March 15, 2017, and March 15, 2018, which will be issued as such units vest in accordance with their terms.
(3)	Shares withheld to satisfy the Issuer's tax withholding obligation upon the vesting of PSU granted on March 15, 2017.
(4)	Shares withheld to satisfy the Issuer's tax withholding obligation upon the vesting of RSU granted on March 17, 2014, March 16, 2015, March 15, 2016, and March 15, 2017.
(5)	The RSU shall vest in equal annual installments over four (4) years from March 15, 2018, provided that the Reporting Person remains in the Issuer's service through each such vesting date.
(6)	Represents the vesting of one-fourth (1/4) of PSUs granted on March 15, 2017 upon the achievement of specified performance goals as certified by the compensation committee of the board of directors of the Issuer on March 15, 2018.
(7)	Each RSU represents the right to receive a specified number of common shares upon the achievement of certain performance goals of the company.

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