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As filed with the Securities and Exchange Commission on June 26, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

WILLDAN GROUP, INC.

(Exact name of registrant as specified in its charter)

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2401 East Katella Avenue, Suite 300

Anaheim, California 92806

(800) 424-9144

(Address of Principal Executive Offices) (Zip Code)

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Willdan Group, Inc.
Amended and Restated 2008 Performance Incentive Plan

(Full title of the plan)

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Creighton K. Early
Chief Financial Officer and Executive Vice President

Willdan Group, Inc.

2401 East Katella Avenue, Suite 300
Anaheim, California 92806

(Name and address of agent for service)

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(800) 424-9144

(Telephone number, including area code, of agent for service)

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Copy to:

John-Paul Motley

Logan Tiari

Cooley LLP

350 South Grand Avenue, Suite 3200

Los Angeles, California 90071
Tel: (213) 561-3204

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Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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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 7(a)(2)(B) of the Securities Act. ☐

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EXPLANATORY NOTE

REGISTRATION OF ADDITIONAL SHARES

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This Registration Statement is filed by Willdan Group, Inc. (the “Registrant”) to register an additional 380,000 shares of the Registrant’s common stock, par value $0.01 per share (the “Common Stock”), issuable pursuant to the Registrant’s Amended and Restated 2008 Performance Incentive Plan (as amended, the “2008 Plan”).  

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The Registrant previously registered shares of its Common Stock for issuance under the 2008 Plan on Registration Statements on Form S-8 filed with the Commission on August 12, 2008 (File No. 333-152951), August 12, 2010 (File No. 333-168787), November 8, 2012 (File No. 333-184823), August 4, 2016 (File No. 333-212907), June 30, 2017 (File No. 333-219133), June 28, 2019 (File No. 333-232438), June 24, 2022 (File No. 333-265833), June 30, 2023 (File No. 333-273079), June 28, 2024 (File No. 333-280582), and June 27, 2025 (File No. 333-288396) (collectively, the “Registration Statements”). Pursuant to General Instruction E to Form S-8, this Registration Statement hereby incorporates by reference the contents of the Registration Statements referenced above except as set forth below.

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PART I

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INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

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The information specified in Item 1 and Item 2 of Part I of Form S-8 is omitted from this filing in accordance with the provisions of Rule 428 under the Securities Act of 1933, as amended (the “Securities Act”) and the introductory note to Part I of the Form S-8 instructions. The documents containing information specified in Part I of Form S-8 will be sent or given to participants as specified by Rule 428(b)(1) of the Securities Act.

PART II

INFORMATION REQUIRED IN REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE

The following documents filed by the Registrant with the Commission are incorporated by reference into this Registration Statement:

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ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL

Not applicable.

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ITEM 8. EXHIBITS

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SIGNATURES

Pursuant to the requirements of the Securities Act, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Anaheim, State of California, on June 26, 2026.

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POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Michael A. Bieber and Creighton K. Early, and each one of them, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him or her and in their name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto and other documents in connection therewith, with the U.S. Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

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Exhibit 5.1

Logan Tiari

T: +1 213 561 3207

ltiari@cooley.com

June 26, 2026

Willdan Group, Inc.

2401 East Katella Avenue, Suite 300

Anaheim, CA 92806

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Re:Willdan Group, Inc. - Registration Statement on Form S-8

Ladies and Gentlemen:

We have acted as counsel to Willdan Group, Inc., a Delaware corporation (the “Company”), in connection with the filing by the Company of a Registration Statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission (the “Commission”) covering the offering of up to 380,000 shares (the “Shares”) of the Company’s common stock, par value $0.01 per share (“Common Stock”) issuable pursuant to the Company’s Amended and Restated 2008 Performance Incentive Plan (the “2008 Plan”).

In connection with this opinion, we have examined and relied upon (a) the Registration Statement and the related prospectus, (b) the Company’s certificate of incorporation and bylaws, each as currently in effect, (c) the 2008 Plan and (d) such other records, documents, opinions, certificates, memoranda and instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies, the accuracy, completeness and authenticity of certificates of public officials, and the due authorization, execution and delivery of all documents by all persons other than by the Company. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the 2008 Plan, the Registration Statement and the related prospectus, will be validly issued, fully paid and nonassessable (except as to shares issued pursuant to deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).

This opinion is limited to the matters expressly set forth in this letter, and no opinion has been or should be implied, or may be inferred, beyond the matters expressly stated.  This opinion speaks only as to law and facts in effect or existing as of the date hereof, and we have no obligation or responsibility to update or supplement this opinion to reflect any facts or circumstances that may hereafter come to our attention or any changes in law that may hereafter occur.

We consent to the filing of this opinion as an exhibit to the Registration Statement.  In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended, or the rules and regulations of the Commission thereunder.

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Willdan Group, Inc.

June 26, 2026

Page Two

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Exhibit 23.2

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Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in this Registration Statement on Form S-8 of Willdan Group, Inc. of our report dated February 26, 2026 relating to the consolidated financial statements and effectiveness of internal control over financial reporting appearing in the Annual Report on Form 10-K of Willdan Group, Inc. for the year ended January 2, 2026.

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