EXHIBIT 23.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (No. 333-143517) of Spire Corporation of our report dated June 23, 2009 relating to the financial statements of Spire Corporation 401(k) Profit Sharing Plan, which appears in this Form 11-K. /s/ Siegrist and Cree, CPA, PC SIEGRIST AND CREE, CPA, PC Wellesley Hills, Massachusetts June 23, 2009