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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OMB Number: 3235-0287
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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 * Maguire Joanne M 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
_____ Officer (give title below)    _____ Other (specify below)
(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)
Code V Amount (A) or (D) Price
COMMON STOCK  11/18/2020    M    582  A $0 (1) 6212  D   
COMMON STOCK  11/18/2020    A    3600  A $0 (2) 9812  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)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)  $0.0  11/18/2020    M     582      11/18/2020 (3) 11/21/2020  COMMON STOCK  582.0  $0  0  D   
RESTRICTED STOCK UNITS (RIGHT TO RECEIVE)  $0.0  11/19/2020    A     410      11/18/2021 (4) 11/19/2021  COMMON STOCK  410.0  $0  410  D   

Explanation of Responses:
(1)  Shares automatically acquired upon the vesting of restricted stock units (RSUs).
(2)  Shares acquired pursuant to vesting of performance stock units (PSUs) earned under 2015 Equity Incentive Plan.
(3)  The restricted stock units (RSUs) became 100% vested as to the shares underlying the RSUs on November 18, 2020.
(4)  The restricted stock units (RSUs) become 100% vested as to the shares underlying the RSUs on November 18, 2021.

Reporting Owners
Reporting Owner Name / Address
Relationships
Director 10% Owner Officer Other
Maguire Joanne M
3475 EAST FOOTHILL BOULEVARD
PASADENA,, CA 91107		 X



Signatures
/s/ Preston Hopson, Attorney-in-fact for Joanne M. Maguire 11/20/2020
**Signature of Reporting Person Date