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 16, 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):

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

o    Soliciting 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 2.02.      Results of Operations and Financial Condition.

On August 16, 2006, Tetra Tech, Inc. (the “Registrant”) reported that it is taking a non-cash charge relating to its historic stock option grants in its third quarter ended July 2, 2006.  The charge effects previously reported diluted earnings per share in such fiscal quarter.  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 16, 2006, reporting a non-cash charge relating to historic stock option grants.

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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 16, 2006	By:	/s/ Janis B. Salin
			Janis B. Salin
			Vice President and General Counsel

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EX-99.1

Exhibit 99.1

August 16, 2006

Tetra Tech Takes Non-Cash Charge for
Historic Stock Option Grants

Pasadena, California.  Tetra Tech, Inc. (NASDAQ:  TTEK) announced today that it will take a charge for stock options granted prior to fiscal 2004 as the result of a voluntary review of historical stock option grant practices by the Company and the Audit Committee with the assistance of outside legal counsel.  The Audit Committee concluded that the Company did not engage in intentional or fraudulent misconduct in the granting of stock options.  The Audit Committee has also determined that, due to unintentional errors, the accounting measurement dates for certain historic stock option grants differed from their actual grant dates.  This one-time charge, representing the cumulative effect of errors related to prior periods, was not material to any previously reported historical period and is not expected to be material to the current fiscal year.  Therefore, there is no restatement of the Company’s previously filed financial statements.

Accordingly, Tetra Tech recorded a non-cash, pre-tax stock-based compensation charge in the third quarter ended July 2, 2006 of $2.3 million for continuing operations and $0.9 million for discontinued operations.  As a result, diluted earnings per share (EPS) from continuing operations for the third quarter of fiscal 2006 was revised from a previously announced $0.17 to $0.14.  Additional details are provided in the Company’s Form 10-Q for the third quarter of fiscal 2006 which was filed today.

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

Any statements made in this release that are not based on historical fact are forward-looking statements.  Any forward-looking statements made in this release represent management’s best judgment as to what may occur in the future.  However, Tetra Tech’s actual outcome and results are not guaranteed and are subject to certain risks, uncertainties and assumptions (“Future Factors”), and may differ materially from what is expressed.  For a description of Future Factors that could cause actual results to differ materially from such forward-looking statements, see the discussion under the section “Risk Factors” included in the Company’s Form 10-K and 10-Q filings with the Securities and Exchange Commission.