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

OMB APPROVAL OMB Number: 3235-0287 Expires: January 31, 2005 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * Chang Mike F   2. Issuer Name and Ticker or Trading Symbol ALPHA & OMEGA SEMICONDUCTOR Ltd [AOSL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director __X__ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) 475 OAKMEAD PARKWAY 3. Date of Earliest Transaction (Month/Day/Year) 02/27/2019 (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 Shares 02/27/2019   A   25,536 (1) A $ 0 4,298,733 (2) D   Common Shares 02/27/2019   A   14,175 (3) A $ 0 4,312,908 (2) (4) D   Common Shares 02/27/2019   A   22,500 (5) A $ 0 4,335,408 (2) (6) D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.		SEC 1474 (9-02)

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

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Chang Mike F 475 OAKMEAD PARKWAY SUNNYVALE, CA 94085	X	X	Chief Executive Officer

Signatures

/s/ Yanbing Hong, attorney-in-fact for Mike F. Chang		03/01/2019
**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)	Represent fully vested common shares ("Bonus Shares") granted by the compensation committee of the Board of Directors of the issuer on February 27, 2019 as part of the bonus payment upon achievement of certain corporate performance goals under the Issuer's Amended and Restated 2017 Executive Incentive Plan, dated November 15, 2017.
(2)	Includes an aggregate of 131,996 shares subject to Restricted Share Unit awards (RSU) 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)	Each PSU represents the actual number of common shares granted on March 15, 2017 upon the achievement of certain performance goals of the company.
(4)	Excludes 28,350 unvested common shares subject to the 2017 PSU which may become vested upon achievement of certain corporate performance goals in the future. Previously, the unvested common shares subject to 2017 PSU have been disclosed in Table II of Form 4 and is now being reported in Table I of this Form 4.
(5)	Represent 22,500 common shares subject to PSU granted on March 15, 2018 ("2018 PSU") that will become vested on March 15, 2019 upon approval and certification on February 27, 2019 by the Compensation Committee that the performance goals under such PSU were satisfied.
(6)	Excludes 67,500 unvested common shares subject to the 2018 PSU which may become vested upon achievement of certain corporate performance goals in the future. Previously, the unvested common shares subject to 2018 PSU have been disclosed in Table II of Form 4 and is now being reported in Table I of this Form 4.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.