Exhibit 99.1 Willdan Group Reports First Quarter Results ANAHEIM, Calif. –May 2, 2024 – Willdan Group, Inc. (“Willdan”) (Nasdaq: WLDN) today reported financial results for its first quarter ended March 29, 2024. “We had an excellent first quarter,” said Mike Bieber, Willdan’s President and Chief Executive Officer. “Revenue, profitability, earnings, and cash flow were above expectations. We saw strength in both government and utility customers, plus strong software sales. The rapid growth in electricity dema ...