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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(Print or Type Responses)

1. Name and Address of Reporting Person * CHRISTENSEN CRAIG L   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, CIO (Last) (First) (Middle) 3475 EAST FOOTHILL BOULEVARD 3. Date of Earliest Transaction (Month/Day/Year) 01/10/2019 (Street) PASADENA,, CA 91107 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 STOCK 01/10/2019   M   3,400 A $ 22.53 40,841 (1) D   COMMON STOCK 01/10/2019   S(2)   3,400 D $ 52.7474 (3) 37,441 D   COMMON STOCK 01/10/2019   S(2)   625 D $ 53 (4) 36,816 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

EMPLOYEE STOCK OPTION (RIGHT TO BUY)

$ 22.53

01/10/2019

M

3,400

11/11/2012(5)

11/11/2019(6)

COMMON STOCK

3,400

$ 22.53

6,600

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
CHRISTENSEN CRAIG L 3475 EAST FOOTHILL BOULEVARD PASADENA,, CA 91107			SVP, CIO

Signatures

/s/ Preston Hopson III, Attorney-in-fact for Craig L. Christensen		01/11/2019
**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)	Amount of securities beneficially owned have been updated to reflect the acquisition of 51 shares of common stock pursuant to the Tetra Tech, Inc. Employee Stock Purchase Plan (ESPP) on December 14, 2018.
(2)	Pursuant to a 10b5-1 automatic trading plan.
(3)	$52.7474 is an average price. Shares were sold at prices ranging from $52.40 to $53.02 per share.
(4)	All shares sold at an exact price.
(5)	The option became exercisable as to 25% of the shares on each anniversary of the grant date.
(6)	The option expires in the current year.

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