X0306 4 2020-03-02 0 0001370450 Willdan Group, Inc. WLDN 0001733724 WHITELAW PAUL MILTON 2401 E. KATELLA AVE SUITE 300 ANAHEIM CA 92806 0 1 0 0 SVP, Business Development Common Stock 2020-03-02 4 A 0 7010 0 A 12471 D Common Stock 2020-03-06 4 F 0 2545 32.68 D 9926 D Common Stock 2020-03-09 4 F 0 157 32.68 D 9769 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 7,010 shares of Common Stock. Includes (i) 444 shares of restricted stock that vest on October 31, 2020 and (ii) an aggregate of 272 shares of Common Stock purchased under the Amended and Restated Willdan Group, Inc. 2006 Employee Stock Purchase Plan, including 128 shares on June 30, 2019 and 144 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). Represents shares of the Issuer's Common Stock withheld for tax withholding purposes in connection with the vesting of restricted stock on March 8, 2020, which restricted stock was granted on March 8, 2017. /s/ Stacy McLaughlin, Attorney-in-fact for Paul Milton Whitelaw 2020-03-12