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):

April 29, 2026

TETRA TECH, INC.

(Exact name of registrant as specified in its charter)

Delaware

0-19655

95-4148514

(State or other jurisdiction
of incorporation)

(Commission
File Number)

(IRS Employer

Identification Number)

3475 East Foothill Boulevard, Pasadena, California 91107

(Address of principal executive office, including zip code)

(626) 351-4664

(Registrant’s telephone number, including area code)

Not Applicable

(Former name or former address, if changed since last report)

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:

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

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

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

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

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading symbol(s)		Name of each exchange on which registered
Common Stock, $0.01 par value		TTEK		The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging Growth Company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 2.02.

Results of Operations and Financial Condition.

On April 29, 2026, Tetra Tech, Inc. (“Tetra Tech”) reported its financial results for the second fiscal quarter ended March 29, 2026. A copy of the press release is attached to this report as Exhibit 99.1.

Exhibit 99.1 attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended.

Item 8.01.

Other Events.

On April 29, 2026, Tetra Tech announced that its Board of Directors has declared a $0.072 per share quarterly cash dividend. The dividend is payable on June 2, 2026 to stockholders of record as of the close of business on May 14, 2026.

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits

99.1

Press Release, dated April 29, 2026, reporting the financial results for Tetra Tech’s second fiscal quarter ended March 29, 2026, and the declaration of a quarterly cash dividend.

104

Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

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

	TETRA TECH, INC.

Date: April 29, 2026	By:	/s/ ROGER R. ARGUS
		Roger R. Argus
		Chief Executive Officer and President

TETRA TECH INC 8-K