Sec Form 4 Filing - LEMMON RICHARD A @ TETRA TECH INC - 2020-11-18

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 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: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person LEMMON RICHARD A 2. Issuer Name and Ticker or Trading Symbol TETRA TECH INC [ TTEK] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP, Corporate Administration (Last) (First) (Middle) 3475 EAST FOOTHILL BOULEVARD 3. Date of Earliest Transaction (MM/DD/YY) 11/18/2020 (Street) PASADENA,, CA91107 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 STOCK 11/18/2020 M 539 A $ 0 ( 1 ) 43,411 D COMMON STOCK 11/18/2020 M 408 A $ 0 ( 1 ) 43,819 D COMMON STOCK 11/18/2020 A 7,556 A $ 0 ( 2 ) 51,375 D COMMON STOCK 11/18/2020 F 5,136 D $ 122 ( 3 ) 46,239 D

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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. O wnership 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 11/18/2020 M 539 11/18/2019( 4 ) 11/18/2022 COMMON STOCK 539 $ 0 1,078 D RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) $ 0 11/18/2020 M 408 11/18/2020( 5 ) 11/21/2023 COMMON STOCK 408 $ 0 1,221 D RESTRICTED STOCK UNITS (RIGHT TO RECEIVE) $ 0 11/19/2020 A 1,230 11/18/2021( 6 ) 11/19/2024 COMMON STOCK 1,230 $ 0 1,230 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other LEMMON RICHARD A 3475 EAST FOOTHILL BOULEVARD PASADENA,, CA91107 SVP, Corporate Administration Signatures /s/ Preston Hopson, Attorney-in-fact for Richard A. Lemmon 11/20/2020 Signature of Reporting Person Date

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 )Represents the combined number of shares withheld to pay the related tax liability on a total of 7,556 performance stock units (PSUs) and 1,954 restricted stock units (RSUs) which vested on 11/18/2020. ( 4 )The restricted stock units (RSUs) become vested as to 25% of the shares underlying the RSUs on November 18, 2019, and on each of anniversary of that date until the RSUs are fully vested. ( 5 )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. ( 6 )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.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* 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).

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