WLDN · Willdan Group, Inc.

Represents shares of restricted stock awarded to the Reporting Person by the Issuer on June 17, 2026, which vest on June 17, 2027.

Includes 1,241 shares of restricted stock that vest on June 17, 2027.

Represents shares of restricted stock awarded to the Reporting Person by the Issuer on June 17, 2026, which vest on June 17, 2027.

Includes 1,241 shares of restricted stock that vest on June 17, 2027.

Represents shares of restricted stock awarded to the Reporting Person by the Issuer on June 17, 2026, which vest on June 17, 2027.

Includes 1,241 shares of restricted stock that vest on June 17, 2027.

Represents shares of restricted stock awarded to the Reporting Person by the Issuer on June 17, 2026, which vest on June 17, 2027.

Includes 1,241 shares of restricted stock that vest on June 17, 2027.

Represents shares of restricted stock awarded to the Reporting Person by the Issuer on June 17, 2026, which vest on June 17, 2027.

Includes 1,241 shares of restricted stock that vest on June 17, 2027.

Represents shares of restricted stock awarded to the Reporting Person by the Issuer on June 17, 2026, which vest on June 17, 2027.

Includes 1,241 shares of restricted stock that vest on June 17, 2027.

The price reported in Column 4 is the weighted average price. These shares were sold in multiple transactions at prices ranging from $92.50 to $93.41, inclusive.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The price reported in Column 4 is the weighted average price. These shares were sold in multiple transactions at prices ranging from $90.50 to $91.46, inclusive. The Reporting Person undertakes to provide to Willdan Group, Inc., any security holder of Willdan Group, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2), footnote (3), footnote (4), and footnote (5).

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The price reported in Column 4 is the weighted average price. These shares were sold in multiple transactions at prices ranging from $91.50 to $92.49, inclusive.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Stock options granted under the Willdan Group, Inc. Amended and Restated 2008 Performance Incentive Plan, which vested in three equal installments on each of March 8, 2018, March 8, 2019, and March 8, 2020.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The price reported in Column 4 is the weighted average price. These shares were sold in multiple transactions at prices ranging from $93.62 to $93.99, inclusive.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Stock options granted under the Willdan Group, Inc. Amended and Restated 2008 Performance Incentive Plan, which vested in three equal installments on each of November 3, 2017, November 3, 2018, and November 3, 2019.

The price reported in Column 4 is the weighted average price. These shares were sold in multiple transactions at prices ranging from $92.50 to $92.85, inclusive. The Reporting Person undertakes to provide to Willdan Group, Inc., any security holder of Willdan Group, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Stock options granted under the Willdan Group, Inc. Amended and Restated 2008 Performance Incentive Plan, which vested in three equal installments on each of November 3, 2017, November 3, 2018, and November 3, 2019.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 3,080 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 1,400 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 20, 2024. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 25, 2026, resulting in the immediate vesting of the restricted stock units as to 15,750 shares of Common Stock.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 20, 2024. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 25, 2026, resulting in the immediate vesting of the restricted stock units as to 3,780 shares of Common Stock.

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 3,080 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 1,400 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 3,080 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 1,400 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 20, 2024. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 25, 2026, resulting in the immediate vesting of the restricted stock units as to 3,780 shares of Common Stock.

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 3,080 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 1,400 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock units on March 20, 2026, which restricted stock was granted on March 20, 2024.

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 3,080 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 1,400 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock units on March 20, 2026, which restricted stock was granted on March 20, 2024.

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 3,080 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 1,400 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock units on March 20, 2026, which restricted stock was granted on March 20, 2024.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock units on March 17, 2026, which restricted stock was granted on March 17, 2025.

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 3,080 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock units on March 17, 2026, which restricted stock was granted on March 17, 2025.

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 3,080 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock units on March 17, 2026, which restricted stock was granted on March 17, 2025.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 11,667 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 17, 2025. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 16, 2026, resulting in the immediate vesting of the restricted stock units as to 4,158 shares of Common Stock.

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 19,250 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 11,667 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 17, 2025. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 16, 2026, resulting in the immediate vesting of the restricted stock units as to 17,326 shares of Common Stock.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 19,250 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 11,667 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 17, 2025. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 16, 2026, resulting in the immediate vesting of the restricted stock units as to 4,158 shares of Common Stock.

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 7, 2023. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 11, 2026, resulting in the immediate vesting of the restricted stock units as to 24,750 shares of Common Stock.

Includes (i) 1,781 shares of restricted stock that vest on June 11, 2026, and (ii) 1,124 shares of restricted stock that vest on June 12, 2026, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 19,250 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 11,667 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 7, 2023. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 11, 2026, resulting in the immediate vesting of the restricted stock units as to 18,810 shares of Common Stock.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 19,250 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 11,667 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1).

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 7, 2023. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 11, 2026, resulting in the immediate vesting of the restricted stock units as to 3,960 shares of Common Stock.

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 7, 2023. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 11, 2026, resulting in the immediate vesting of the restricted stock units as to 3,960 shares of Common Stock.

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock on March 7, 2026, which restricted stock was granted on March 7, 2023.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 19,250 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 11,667 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock on March 7, 2026, which restricted stock was granted on March 7, 2023.

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of restricted stock on March 7, 2026, which restricted stock was granted on March 7, 2023.

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, and (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The price reported in Column 4 is the weighted average price. These shares were sold in multiple transactions at prices ranging from $81.80 to $81.94, inclusive. The Reporting Person undertakes to provide to Willdan Group, Inc., any security holder of Willdan Group, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.

Includes (i) 1,781 shares of restricted stock that vest on June 11, 2026 and (ii) 1,124 shares of restricted stock that vest on June 12, 2026, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Represents shares of restricted stock units awarded to the Reporting Person by the Issuer on March 3, 2026, which vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Includes (i) 5,625 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027 and (iv) 7,600 shares of restricted stock that vest on March 7, 2026, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Includes 176 shares of Common Stock purchased under the Amended and Restated Willdan Group, Inc. 2006 Employee Stock Purchase Plan on December 31, 2025.

Represents shares of restricted stock units awarded to the Reporting Person by the Issuer on March 3, 2026, which vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 19,250 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, (iii) 11,667 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027 and (iv) 4,434 shares of restricted stock that vest on March 7, 2026, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Includes 154 shares of Common Stock purchased under the Amended and Restated Willdan Group, Inc. 2006 Employee Stock Purchase Plan on December 31, 2025.

Represents shares of restricted stock units awarded to the Reporting Person by the Issuer on March 3, 2026, which vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Includes (i) 4,500 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 4,620 shares of restricted stock units that vest in three substantially equal installments on each of March 17, 2026, March 17, 2027 and March 17, 2028, (iii) 2,800 shares of restricted stock units that vest in two substantially equal installments on each of March 20, 2026 and March 20, 2027 and (iv) 934 shares of restricted stock that vest on March 7, 2026, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

Includes 154 shares of Common Stock purchased under the Amended and Restated Willdan Group, Inc. 2006 Employee Stock Purchase Plan on December 31, 2025.

The price reported in Column 4 is the weighted average price. These shares were sold in multiple transactions at prices ranging from $106.00 to $106.87, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (1).

Includes (i) 1,781 shares of restricted stock that vest on June 11, 2026 and (ii) 1,124 shares of restricted stock that vest on June 12, 2026, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.