PROMISSORYNOTE

Exhibit 10.2

PROMISSORY NOTE

References in the shaded area are for Lender’s use only and do not limit the applicability of this document to any particular loan or item.

Any item above containing “***” has been omitted due to text length limitations.

PROMISE TO PAY. Willdan Group, Inc. (“Borrower”) promises to pay to Orange County Business Bank (“Lender”), or order, in lawful money of the United States of America, the principal amount of Eight Million & 00/100 Dollars ($8,000,000.00) or so much as may be outstanding, together with interest on the unpaid outstanding principal balance of each advance. Interest shall be calculated from the date of each advance until repayment of each advance.

PAYMENT. Borrower will pay this loan in full immediately upon Lender’s demand. If no demand is made, Borrower will pay this loan in one payment of all outstanding principal plus all accrued unpaid interest on July 31, 2007. In addition, Borrower will pay regular monthly payments of all accrued unpaid interest due as of each payment date, beginning February 28, 2007, with all subsequent interest payments to be due on the last day of each month after that. Unless otherwise agreed or required by applicable law, payments will be applied first to any accrued unpaid interest; then to principal; and then to any late charges. The annual interest rate for this Note is computed on a 365/360 basis; that is, by applying the ratio of the annual interest rate over a year of 360 days, multiplied by the outstanding principal balance, multiplied by the actual number of days the principal balance is outstanding. Borrower will pay Lender at Lender’s address shown above or at such other place as Lender may designate in writing.

VARIABLE INTEREST RATE. The interest rate on this Note is subject to change from time to time based on changes in an independent index which is the Wall Street Journal Prime Rate as quoted in the Western Edition of the Wall Street Journal (the “Index”). The Index is not necessarily the lowest rate charged by Lender on its loans. If the Index becomes unavailable during the term of this loan, Lender may designate a substitute index after notifying Borrower. Lender will tell Borrower the current Index rate upon Borrower’s request. The interest rate change will not occur more often than each day. Borrower understands that Lender may make loans based on other rates as well. The Index currently is 8.250%. The interest rate to be applied to the unpaid principal balance during this Note will be at a rate of 0.250 percentage points over the Index, resulting in an initial rate of 8.500%. NOTICE: Under no circumstances will the interest rate on this Note be more than the maximum rate allowed by applicable law.

PREPAYMENT; MINIMUM INTEREST CHARGE. Borrower agrees that all loan fees and other prepaid finance charges are earned fully as of the date of the loan and will not be subject to refund upon early payment (whether voluntary or as a result of default), except as otherwise required by law. In any event, even upon full prepayment of this Note, Borrower understands that Lender is entitled to a minimum interest charge of $100.00. Other than Borrower’s obligation to pay any minimum interest charge, Borrower may pay without penalty all or a portion of the amount owed earlier than it is due. Early payments will not, unless agreed to by Lender in writing, relieve Borrower of Borrower’s obligation to continue to make payments of accrued unpaid interest. Rather, early payments will reduce the principal balance due. Borrower agrees not to send Lender payments marked “paid in full”, “without recourse”, or similar language. If Borrower sends such a payment, Lender may accept it without losing any of Lender’s rights under this Note, and Borrower will remain obligated to pay any further amount owed to Lender. All written communications concerning disputed amounts, including any check or other payment instrument that indicates that the payment constitutes “payment in full” of the amount owed or that is tendered with other conditions or limitations or as full satisfaction of a disputed amount must be mailed or delivered to: Orange County Business Bank, 4675 MacArthur Court Newport Beach, CA 92660.

LATE CHARGE. If a payment is 10 days or more late, Borrower will be charged 5.000% of the regularly scheduled payment or $5.00, whichever is greater.

INTEREST AFTER DEFAULT. Upon default, the interest rate on this Note shall, if permitted under applicable law, immediately increase by adding a 6.000 percentage point margin (“Default Rate Margin”). The Default Rate Margin shall also apply to each succeeding interest rate change that would have applied had there been no default.

DEFAULT. Each of the following shall constitute an event of default (“Event of Default”) under this Note:

Payment Default. Borrower fails to make any payment when due under this Note within ten (10) days of due date.

Other Defaults. Borrower fails to comply with or to perform any other material term, obligation, covenant or condition contained in this Note or in any of the related documents or to comply with or to perform any term, obligation, covenant or condition contained in any other agreement between Lender and Borrower within twenty (20) days of notice from Lender.

False Statements. Any warranty, representation or statement made or furnished to Lender by Borrower or on Borrower’s behalf under this Note or the related documents is false or misleading in any material respect, either now or at the time made or furnished.

Insolvency. The dissolution or termination of Borrower’s existence as a going business, the insolvency of Borrower, the appointment of a receiver for any part of Borrower’s property, any assignment for the benefit of creditors, any type of creditor workout, or the commencement of any proceeding under any bankruptcy or insolvency laws by or against Borrower.

Creditor or Forfeiture Proceedings. Commencement of foreclosure or forfeiture proceedings, whether by judicial proceeding, self-help, repossession or any other method, by any creditor of Borrower or by any governmental agency against any collateral securing the loan. This includes a garnishment of any of Borrower’s accounts, including deposit accounts, with Lender. However, this Event of Default shall not apply if there is a good faith dispute by Borrower as to the validity or reasonableness of the claim which is the basis of the creditor or forfeiture proceeding and if Borrower gives Lender written notice of the creditor or forfeiture proceeding and deposits with Lender monies or a surety bond for the creditor or forfeiture proceeding, in an amount determined by Lender, in its sole discretion, as being an adequate reserve or bond for the dispute.

Events Affecting Guarantor. Any of the preceding events occurs with respect to any Guarantor of any of the indebtedness or any Guarantor dies or becomes incompetent, or revokes or disputes the validity of, or liability under, any guaranty of the indebtedness evidenced by this Note. In the event of a death, Lender, at its option, may, but shall not be required to, permit the Guarantor’s estate to assume unconditionally the obligations arising under the guaranty in a manner satisfactory to Lender, and, in doing so, cure any Event of Default.

Adverse Change. A material adverse change occurs in Borrower’s financial condition, which causes Lender to believe the prospect of payment or performance of this Note is impaired.

Cure Provisions. If any default, other than a default in payment is curable and if Borrower has not been given a notice of a breach of the same provision of this Note within the preceding twelve (12) months, it may be cured if Borrower, after receiving written notice from Lender demanding cure of such default: (1) cures the default within twenty (20) days; or (2) if the cure requires more than twenty (20) days, immediately initiates steps which Lender deems in Lender’s sole discretion to be sufficient to cure the default and thereafter continues and completes all reasonable and necessary steps sufficient to produce compliance as soon as reasonably practical.

LENDER’S RIGHTS. Upon default, Lender may declare the entire unpaid principal balance under this Note and all accrued unpaid interest immediately. due, and then Borrower will pay that amount.

ATTORNEYS’ FEES; EXPENSES. Lender may hire or pay someone else to help collect this Note if Borrower does not pay. Borrower will pay reasonable attorney fees. This includes, subject to any limits under applicable law, Lender’s attorneys’ fees and Lender’s legal expenses, whether or not there is a lawsuit, including attorneys’ fees, expenses for bankruptcy proceedings (including efforts to modify or vacate any automatic stay or injunction), and appeals. Borrower also will pay any court costs, in addition to all other sums provided by law.

GOVERNING LAW. This Note will be governed by federal law applicable to Lender and, to the extent not preempted by federal law, the laws of the State of California without regard to its conflicts of law provisions. This Note has been accepted by Lender in the State of California.

CHOICE OF VENUE. If there is a lawsuit, Borrower agrees upon Lender’s request to submit to the jurisdiction of the courts of Orange County, State of California.

DISHONORED ITEM FEE. Borrower will pay a fee to Lender of $45.00 if Borrower makes a payment on Borrower’s loan and the check or preauthorized charge with which Borrower pays is later dishonored.

COLLATERAL. Borrower acknowledges this Note is secured by the following collateral described in the security instrument listed herein: inventory, chattel paper, accounts, equipment and general intangibles described in a Commercial Security Agreement dated January 31, 2007.

LINE OF CREDIT. This Note evidences a revolving line of credit. Advances under this Note, as well as directions for payment from Borrower’s accounts, may be requested orally or in writing by Borrower or as provided in this paragraph. Lender may, but need not, require that all oral requests be confirmed in writing. The following persons currently are authorized, except as provided in this paragraph, to request advances and authorize payments under the line of credit until Lender receives from Borrower, at Lender’s address shown above, written notice of revocation of their authority: Win S. Westfall; Roy L. Gill; Mallory McCamant; and Kate Mai Nguyen. In addition to requesting advances orally or in writing, advances may be requested via online banking or loan sweep. Borrower agrees to be liable for all sums either: (A) advanced in accordance with the instructions of an authorized person or (B) credited to any of Borrower’s accounts with Lender. The unpaid principal balance owing on this Note at any time may be evidenced by endorsements on this Note or by Lender’s internal records, including daily computer print-outs. Lender will have no obligation to advance funds under this Note if: (A) Borrower or any guarantor is in default under the terms of this Note or any agreement that Borrower or any guarantor has with Lender, including any agreement made in connection with the signing of this Note; (B) Borrower or any guarantor ceases doing business or is insolvent; (C) any guarantor seeks, claims or otherwise attempts to limit, modify or revoke such guarantor’s guarantee of this Note or any other loan with Lender; or (D) Borrower has applied funds provided pursuant to this Note for purposes other than those authorized by Lender.

ADDITIONAL PROVISION.

Two million dollars ($2,000,000.00) of the revolving line of credit can be converted to two term loans and is subject to the following provisions.

A maximum one million dollars ($1,000,000.00) for expenses incurred to start up a new division and or business unit of Borrower can be converted to a multiple advance loan for up to two (2) years. At the end of the multiple advance period, the total amount advanced up to one million dollars ($1,000,000.00) will be converted to a fully amortized term loan for a period of up to three (3) years.

A maximum one million dollars ($1,000,000.00) for the acquisition of other companies can be converted to a fully amortized term loan for a period of up to three years.

Once the conversion of both term loans has been executed, the amount available for borrowing hereunder shall be permanently reduced by the total of such amount.

Once a formula base credit line is in effect, Borrower shall deliver to Lender as of the end of each month a Borrowing Base Certificate, calculation of Ineligible Accounts, detailed Accounts Receivable Aging and Accounts Payable Aging and Work in Process Report within forty five (45) days of each month end.

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SUCCESSOR INTERESTS. The terms of this Note shall be binding upon Borrower, and upon Borrower’s heirs, personal representatives, successors and assigns, and shall inure to the benefit of Lender and its successors and assigns.

NOTIFY US OF INACCURATE INFORMATION WE REPORT TO CONSUMER REPORTING AGENCIES. Please notify us if we report any inaccurate information about your account(s) to a consumer reporting agency. Your written notice describing the specific inaccuracy(ies) should be sent to us at the following address: Orange County Business Bank 4675 MacArthur Court, Suite 100 Newport Beach, CA 92660.

GENERAL PROVISIONS. This Note is payable on demand. The inclusion of specific default provisions or rights of Lender shall not preclude Lender’s right to declare payment of this Note on its demand. If any part of this Note cannot be enforced, this fact will not affect the rest of the Note. Lender may delay or forgo enforcing any of its rights or remedies under this Note without losing them. Borrower and any other person who signs, guarantees or endorses this Note, to the extent allowed by law, waive any applicable statute of limitations, presentment, demand for payment, and notice of dishonor. Upon any change in the terms of this Note, and unless otherwise expressly stated in writing, no party who signs this Note, whether as maker, guarantor, accommodation maker or endorser, shall be released from liability. All such parties agree that Lender may renew or extend (repeatedly and for any length of time) this loan or release any party or guarantor or collateral; or impair, fail to realize upon or perfect Lender’s security interest in the collateral; and take any other action deemed necessary by Lender without the consent of or notice to anyone. All such parties also agree that Lender may modify this loan without the consent of or notice to anyone other than the party with whom the modification is made. The obligations under this Note are joint and several.

PRIOR TO SIGNING THIS NOTE, BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS OF THIS NOTE, INCLUDING THE VARIABLE INTEREST RATE PROVISIONS. BORROWER AGREES TO THE TERMS OF THE NOTE.

BORROWER ACKNOWLEDGES RECEIPT OF A COMPLETED COPY OF THIS PROMISSORY NOTE.

BORROWER:

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