X0306 4 2020-03-02 0 0001370450 Willdan Group, Inc. WLDN 0001395188 Brisbin Thomas Donald 2401 EAST KATELLA AVENUE SUITE 300 ANAHEIM CA 92806 1 1 0 1 Chief Executive Officer Chairman of the Board Common Stock 2020-03-02 4 A 0 49070 0 A 252554 D Common Stock 2020-03-06 4 F 0 34095 32.68 D 218459 D Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 6, 2018. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee on March 2, 2020, resulting in the immediate vesting of the restricted stock units as to 49,070 shares of Common Stock. Includes an aggregate of 711 shares of Common Stock purchased under the Amended and Restated Willdan Group, Inc. 2006 Employee Stock Purchase Plan, including 430 shares on June 30, 2019 and 281 shares on December 31, 2019. Represents shares of the Issuer's Common Stock withheld for tax withholding purposes in connection with the vesting of the performance-based restricted stock units referenced in footnote (1). /s/ Stacy McLaughlin Attorney-in-Fact for Thomas D. Brisbin 2020-03-12