8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C.  20549

FORM 8-K

CURRENT  REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):

August 11, 2006

TETRA TECH, INC.

(Exact name of registrant as specified in its charter)

Delaware	0-19655	95-4148514
(State or other jurisdiction	(Commission	(IRS Employer
of incorporation)	File Number)	Identification Number)

3475 East Foothill Boulevard, Pasadena, California  91107

(Address of principal executive office and zip code)

(626) 351-4664

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

oWritten communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

oSoliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

oPre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

oPre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01.Other Events.

On August 11, 2006, Tetra Tech, Inc. (the “Registrant”) issued a press release to announce its intention to submit a Rule 12b-25 filing related to its Quarterly Report on Form 10-Q for the fiscal quarter ended July 2, 2006.  A copy of the press release issued by the Registrant concerning the foregoing is furnished herewith as Exhibit 99.1 and is incorporated herein by reference.

The information contained herein and in the accompanying exhibit shall not be incorporated by reference into any filing of the Registrant, whether made before or after the date hereof, regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference to such filing.  The information in this Current Report, including the exhibit hereto, shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended.

Item 9.01.Financial Statements and Exhibits.

(d)Exhibits

99.1Press Release, dated August 11, 2006, regarding the Registrant’s intention to file a Form 12b-25 related to its Quarterly Report on Form 10-Q for the fiscal quarter ended July 2, 2006.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

		TETRA TECH, INC.
Date:	August 11, 2006	By:	/s/ David W. King
			David W. King
			Chief Financial Officer

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EX-99.1

Exhibit 99.1

August 11, 2006

Tetra Tech to Seek Five-Day Extension for Filing 10-Q

Pasadena, California.  Tetra Tech, Inc. (NASDAQ:  TTEK) announced today that it intends to submit a Rule 12b-25 filing related to its Quarterly Report on Form 10-Q for the fiscal quarter ended July 2, 2006.  The Company is in the process of voluntarily reviewing its historical stock option grant practices.

The Company has completed its review of stock options granted in fiscal years 2006, 2005 and 2004, and has preliminarily determined there is no material impact on its financial statements from options granted during those periods.  The Company is now reviewing stock options granted in prior periods.  The review to date indicates no intentional misstatements.  The Company currently believes that it will complete its review in the next few days and anticipates filing its Quarterly Report by August 16, 2006 as permitted by Rule 12b-25.

About Tetra Tech (www.tetratech.com)

Tetra Tech is a leading provider of consulting, engineering and technical services.  With approximately 7,500 associates located in the United States and internationally, the Company supports commercial and government clients in the areas of resource management and infrastructure.  Tetra Tech’s services include research and development, applied science and technology, engineering design, program management, construction management, and operations and maintenance.

CONTACT: Mike Bieber, (626) 351-4664

Forward-Looking Statements

This news release contains forward-looking statements that are subject to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include information concerning future events and the future financial performance of Tetra Tech that involve risks and uncertainties. Readers are cautioned that these forward-looking statements are only predictions and may differ materially from actual future events or results. Readers are urged to read the documents filed by Tetra Tech with the SEC, specifically the most recent reports on Form 10-K, 10-Q, and 8-K, each as it may be amended from time to time, which identify risk factors that could cause actual results to differ materially from the forward-looking statements. Among the important factors or risks that could cause actual results or events to differ materially from those in the forward-looking statements in this release are: fluctuations in quarterly operating results; the impact of downturns in the financial markets and reductions in government budgets; volatility of common stock value; concentration of revenues from government agencies and funding disruptions by these agencies; failure to properly manage projects; acquisition strategy risks; management of growth strategy; use of the percentage-of-completion method of accounting; adverse resolution of an IRS examination; loss of key personnel or the inability to attract and retain qualified personnel; implementation of the enterprise resource planning system; international operations risks; credit risks associated with commercial clients; violations of government contractor regulations; competitive bidding for government contracts; the affect of a negative government audit; the inability to accurately estimate contract risks, revenue, and costs; backlog cancellation and adjustments; client base consolidation; failure of partners to perform on joint projects; inability to find qualified subcontractors; changes in existing environmental laws, regulations, or programs; competition; restrictive covenants in debt agreements; risks of professional and other liabilities; adverse resolution of litigation; conflict of interest issues; changes in accounting for equity-related compensation; expenses associated with corporate governance; and disruption of operations due to computer viruses or terrorism. Any projections in this release

are based on limited information currently available to Tetra Tech, which is subject to change. Although any such projections and the factors influencing them will likely change, Tetra Tech will not necessarily update the information, since Tetra Tech will only provide guidance at certain points during the year. Readers should not place undue reliance on forward-looking statements since such information speaks only as of the date of this release.

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