UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934 (Amendment No.     )

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Definitive Proxy Statement

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Soliciting Material Pursuant to §240.14a-12

Tetra Tech, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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TETRA TECH, INC.

TETRA TECH, INC.

C/O COMPUTERSHARE

P.O. BOX 43070

PROVIDENCE, RI 02940-3070

Meeting Information

Meeting Type:  Annual Meeting

For holders as of:  January 04, 2019

Date:  February 28, 2019       Time:  10:00 AM PST

Location:

The Westin Pasadena

191 N. Los Robles Avenue

Pasadena, CA 91101

You are receiving this communication because you hold shares in the   above named company.

This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side).

We encourage you to access and review all of the important information contained in the proxy materials before voting.

See the reverse side of this notice to obtain proxy materials and voting instructions.

Proxy Materials Available to VIEW or RECEIVE:

1. Notice & Proxy Statement    2. Annual Report    3. Shareholder Letter

How to View Online:

Have the information that is printed in the box marked by the arrow Ú XXXX XXXX XXXX XXXX (located on the following page) and visit: www.proxyvote.com.

How to Request and Receive a PAPER or E-MAIL Copy:

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1) BY INTERNET:

www.proxyvote.com

2) BY TELEPHONE:

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Vote In Person: Many stockholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance.  At the meeting, you will need to request a ballot to vote these shares.

Vote By Internet: To vote now by Internet, go to www.proxyvote.com.  Have the information that is printed in the box marked by the arrow Ú  XXXX XXXX XXXX XXXX available and follow the instructions.

Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card.

Voting items

The Board of Directors recommends you vote
FOR each of the following director nominees:

1.

Election of Directors

Nominees

1A

Dan L. Batrack

NOTE: In their discretion, the proxies are authorized to vote on such other business as may properly come before the meeting or any postponement or adjournment thereof.

1B

Gary R. Birkenbeuel

1C

Hugh M. Grant

1D

Patrick C. Haden

1E

J. Christopher Lewis

1F

Joanne M. Maguire

1G

Kimberly E. Ritrievi

1H

Albert E. Smith

1I

J. Kenneth Thompson

1J

Kirsten M. Volpi

The Board of Directors recommends you vote
FOR proposals 2 and 3.

2

To approve, on an advisory basis, the
Company’s executive compensation;

3

To ratify the appointment of
PricewaterhouseCoopers LLP as the
Company’s independent registered
public accounting firm for fiscal year 2019.