Statement of Changes in Beneficial Ownership (4)

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
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* BATRACK DAN L	2. Issuer Name and Ticker or Trading Symbol TETRA TECH INC [ TTEK ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) CHAIRMAN AND CEO
(Last) (First) (Middle) 3475 EAST FOOTHILL BOULEVARD	3. Date of Earliest Transaction (MM/DD/YYYY) 11/18/2020
(Street) PASADENA,, CA 91107 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
COMMON STOCK	11/18/2020		M		43463	A	$47.95	265870	D
COMMON STOCK	11/18/2020		M		15649	A	$40.80	281519	D
COMMON STOCK	11/18/2020		S		59112	D	$123.7636 ⁽¹⁾	222407	D
COMMON STOCK	11/18/2020		M		5308	A	$0 ⁽²⁾	227715	D
COMMON STOCK	11/18/2020		M		4277	A	$0 ⁽²⁾	231992	D
COMMON STOCK	11/18/2020		A		71428	A	$0 ⁽³⁾	303420	D
COMMON STOCK	11/18/2020		F		48695	D	$122 ⁽⁴⁾	254725	D

*Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)*
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		7. Title and Amount of Securities Underlying Derivative Security (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)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)
STOCK OPTION (RIGHT TO BUY)	$47.95	11/18/2020		M			43463	11/17/2018 ⁽⁵⁾	11/17/2027 ⁽⁶⁾	COMMON STOCK	43463.0	$0	14487	D
STOCK OPTION (RIGHT TO BUY)	$40.8	11/18/2020		M			15649	11/18/2017 ⁽⁵⁾	11/18/2026 ⁽⁶⁾	COMMON STOCK	15649.0	$0	0	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	$0.0	11/18/2020		M			5308	11/18/2019 ⁽⁷⁾	11/18/2022	COMMON STOCK	5308.0	$0	10616	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	$0.0	11/18/2020		M			4277	11/18/2020 ⁽⁸⁾	11/21/2023	COMMON STOCK	4277.0	$0	12828	D
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)	$0.0	11/19/2020		A		13115		11/18/2021 ⁽⁹⁾	11/19/2024	COMMON STOCK	13115.0	$0	13115	D

Explanation of Responses:
(1)	$123.7636 is an average price. Shares were sold at prices ranging from $121.91 to $127.03 per share.
(2)	Shares automatically acquired upon the vesting of restricted stock units (RSUs).
(3)	Shares acquired pursuant to vesting of performance stock units (PSUs) earned under 2015 Equity Incentive Plan.
(4)	Represents the combined number of shares withheld to pay the related tax liability on a total of 71,428 performance stock units (PSUs) and 18,776 restricted stock units (RSUs) which vested on 11/18/2020.
(5)	The option becomes exercisable as to 25% of the shares on each anniversary of the grant date.
(6)	The option granted expires 10 years after the grant date.
(7)	The RSUs become vested as to 25% of the shares on November 18, 2019, and the anniversary of that date going forward until fully vested.
(8)	The RSUs become vested as to 25% of the shares on November 18, 2020, and the anniversary of that date going forward until fully vested.
(9)	The RSUs become vested as to 25% of the shares on November 18, 2021, and the anniversary of that date going forward until fully vested.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
BATRACK DAN L 3475 EAST FOOTHILL BOULEVARD PASADENA,, CA 91107	X		CHAIRMAN AND CEO