Willdan Group Inc

Use of Non-GAAP Financial Measures

“Adjusted EBITDA,” defined as net income (loss) plus interest expense, income tax expense (benefit), stock-based compensation, interest accretion, depreciation and amortization, gain (loss) on sale of equipment, and tax benefit distribution, is a non-GAAP financial measure. Adjusted EBITDA is a supplemental measure used by Willdan’s management to measure Willdan’s operating performance. Willdan believes Adjusted EBITDA is useful because it allows Willdan’s management to evaluate its operating performance and compare the results of its operations from period to period and against its peers without regard to its financing methods, capital structure and non-operating expenses. Willdan uses Adjusted EBITDA to evaluate its performance for, among other things, budgeting, forecasting and incentive compensation purposes.

Certain items excluded from Adjusted EBITDA are significant components in understanding and assessing a company’s financial performance, such as a company’s costs of capital and stock-based compensation, as well as the historical costs of depreciable assets. A reconciliation of net income as reported in accordance with GAAP to Adjusted EBITDA is provided below.

“Adjusted Net Income,” defined as net income plus stock-based compensation, intangible amortization, interest accretion, refinancing costs, and tax benefit distribution, each net of tax, is a non-GAAP financial measure.

“Adjusted Diluted EPS,” defined as net income plus stock-based compensation, intangible amortization, interest accretion, refinancing costs, and tax benefit distribution, each net of tax, all divided by the diluted weighted-average shares outstanding, is a non-GAAP financial measure. Adjusted Net Income and Adjusted Diluted EPS are supplemental measures used by Willdan’s management to measure its operating performance. Willdan believes Adjusted Net Income and Adjusted Diluted EPS are useful because they allow Willdan’s management to more closely evaluate and explain the operating results of Willdan’s business by removing certain non-operating expenses. Reconciliations of net income as reported in accordance with GAAP to Adjusted Net Income and diluted EPS as reported in accordance with GAAP to Adjusted Diluted EPS are provided below.

Willdan’s definitions of Adjusted EBITDA, Adjusted Net Income and Adjusted Diluted EPS have limitations as analytical tools and may differ from other companies reporting similarly named measures or from similarly named measures Willdan has reported in prior periods. These measures should be considered in addition to, and not as a substitute for, or superior to, other measures of financial performance prepared in accordance with GAAP, such as contract revenue, net income and diluted EPS.

Willdan Group, Inc. and Subsidiaries

Reconciliation of GAAP Net Income to Adjusted EBITDA

(in thousands)

(Non-GAAP Measure)

4. Approval, on a non-binding advisory basis, of the frequency of future advisory votes on our named executive officer compensation. Proposals — The Board of Directors recommend a vote FOR all the nominees listed, FOR Proposals X – X and for every X YEARS on Proposal X. One Year Two Years Three Years Abstain 01 - Thomas D. Brisbin 04 - Cynthia A. Downes 07 - Mohammad Shahidehpour 02 - Michael A. Bieber 05 - Dennis V. McGinn 03 - Steven A. Cohen 06 - Wanda K. Reder 1UPX For Withhold For Withhold For Withhold The Sample Company Proposals — The Board of Directors recommend a vote FOR all the nominees listed, FOR Proposal 2, FOR Proposal 3, ONE YEAR for Proposal 4, and FOR Proposal 5. A 0456PB 2. Ratification of the appointment of Crowe LLP as the independent registered public accounting firm for the year ending January 2, 2026. 3. Approval, on a non-binding advisory basis, of our named executive officer compensation. 1. Election of seven members of the Board of Directors, each to serve a one-year term or until their successors are duly elected and qualified, or until their earlier resignation or removal: For Against Abstain For Against Abstain Please sign exactly as name appears on this Proxy Card. Joint owners should each sign. When signing as attorney, executor, administrator, trustee, guardian or in another representative capacity, please give full title as such. Corporations and partnerships shall sign in full corporate or partnership name by an authorized person. Date (mm/dd/yyyy) — Please print date below. Signature 1 — Please keep signature within the box. Signature 2 — Please keep signature within the box. B Authorized Signatures — This section must be completed for your vote to be counted. — Date and Sign Below Note: At 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. Annual Meeting Proxy Card Using a black ink pen, mark your votes with an X as shown in this example. Please do not write outside the designated areas. q IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE.q 5. Approval of an amendment to the Company’s 2008 Performance Incentive Plan (the “2008 Plan”), including an increase in the number of shares available for grant under the 2008 Plan. MMMMMMMMMMMM MMMMMMMMM 1234 5678 9012 345 652361 If no electronic voting, delete QR code and control # 000001MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2 ADD 3 ADD 4 ADD 5 ADD 6 ENDORSEMENT_LINE______________ SACKPACK_____________ MMMMMMMMMMMMMMM C123456789 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext 2024 MR A SAMPLE (THIS AREA IS SET UP TO ACCOMMODATE 140 CHARACTERS) MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND C 1234567890 J N T MMMMMMM You may vote online or by phone instead of mailing this card. Online Before the Annual Meeting. Go to www.investorvote.com/WLDN or scan the QR code — login details are located in the shaded bar below. During the Annual Meeting. Go to https://meetnow.global/ML2X4HH. Have the number that is printed in the shaded bar below available and follow the instructions on the reverse side. Your vote matters – here’s how to vote! Phone Call toll free 1-800-652-VOTE (8683) within the USA, US territories and Canada

Small steps make an impact. Help the environment by consenting to receive electronic delivery, sign up at www.investorvote.com/WLDN Proxy Solicited on Behalf of the Board of Directors of the Company for the Annual Meeting to be held on June 12, 2025 The undersigned stockholder of Willdan Group, Inc., a Delaware corporation (the “Company”), hereby appoints Creighton Early and Micah Chen, or any of them acting alone, as proxies for the undersigned, each with full power of substitution, to represent and vote, as designated on the reverse side of this ballot, all of the shares of common stock of the Company that the undersigned is entitled to vote at the Annual Meeting of Stockholders of the Company to be held on June 12, 2025 at 10:00 a.m. Pacific Daylight Time at https://meetnow.global/ML2X4HH, and at any adjournment or postponement thereof (with discretionary authority under Proposal 1 to vote for a substitute nominee if any nominee is unable to serve or for good cause will not serve) and on such other matters as may properly come before said meeting, and otherwise to represent the undersigned at the meeting with all powers possessed by the undersigned as if the undersigned was present at the meeting. The undersigned hereby acknowledges receipt of the Notice of the Annual Meeting of Stockholders and the accompanying Proxy Statement. The Board of Directors has fixed the close of business on April 15, 2025 as the record date for determining the stockholders entitled to notice of and to vote at the Annual Meeting and at any adjournment or postponement thereof. Only stockholders of record of the Company’s common stock, $0.01 par value per share, at the close of business on that date will be entitled to notice of and to vote at the Annual Meeting and at any adjournment or postponement thereof. The votes entitled to be cast by the undersigned will be cast as instructed on the reverse side hereof. If this Proxy is executed but no instruction is given, the votes entitled to be cast by the undersigned will be cast “FOR” each of the nominees for director, “FOR” Proposal 2, “FOR” Proposal 3, “ONE YEAR” for Proposal 4, and “FOR” Proposal 5. The votes entitled to be cast by the undersigned will be cast in the discretion of the Proxy holder on any other matter that may properly come before the Annual Meeting or any adjournment or postponement thereof. The signer hereby revokes all Proxies heretofore given by the signer with respect to said meeting or any adjournment or postponement thereof. YOUR VOTE IS IMPORTANT! PLEASE VOTE, SIGN, DATE AND RETURN THIS PROXY CARD PROMPTLY USING THE ENCLOSED ENVELOPE OR VOTE BY TELEPHONE OR INTERNET PURSUANT TO THE INSTRUCTIONS ON THE REVERSE SIDE. Proxy — Willdan Group, Inc. C Non-Voting Items q IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE.q Change of Address — Please print new address below. Comments — Please print your comments below. The 2025 Annual Meeting of Stockholders of WILLDAN GROUP, INC. will be held on Thursday, June 12, 2025, 10:00 A.M. Pacific Daylight Time, virtually via the internet at https://meetnow.global/ML2X4HH. To access the virtual meeting, you must have the information that is printed in the shaded bar located on the reverse side of this form.