[FORM 10-K (Mark One) ý For the fiscal year ended August 31, 2011 OR o For the transition period from to SemiLEDs Corporation Delaware 20-2735523 3F, No. 11 Ke Jung Rd., Chu-Nan Site, 350 +886-37-586788 Title of each class Name of each exchange on which registered Common stock, par value $0.0000056 per share The NASDAQ Global Select Market None o] [QuickLinks -- Click here to rapidly navigate through this document List of Subsidiaries Name Jurisdiction of Percentage of Majority-Owned Subsidiaries: SemiLEDs Optoelectronics Co., Ltd. Taiwan 100 % Helios Crew Corporation Delaware 100 % Silicon Base Development, Inc. Taiwan 100 % SemiLEDs International Corporation Ltd. Hong Kong 100 % Ning Xiang Technology Co., Ltd. Taiwan] [QuickLinks -- Click here to rapidly navigate through this document Consent of Independent Registered Public Accounting Firm The Board of Directors and Stockholders We consent to the incorporation by reference in the registration statement (No. 333-171107) on Form S-8 of SemiLEDs Corporation of our report dated October 26, 2010, except for the amendment to the preferred stock automatic conversion provisions] [QuickLinks -- Click here to rapidly navigate through this document Consent of Independent Registered Public Accounting Firm The Board of Directors and Stockholders We consent to the incorporation by reference in the registration statement (No. 333-171107) on Form S-8 of SemiLEDs Corporation of our report dated November 22, 2011 with respect to the consolidated balance sheet of SemiLEDs Corporation and] [QuickLinks -- Click here to rapidly navigate through this document CERTIFICATION OF CHIEF EXECUTIVE OFFICER I, Trung Tri Doan, certify that: 1. 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such] [QuickLinks -- Click here to rapidly navigate through this document CERTIFICATION OF CHIEF FINANCIAL OFFICER I, David Young, certify that: 1. 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements] [QuickLinks -- Click here to rapidly navigate through this document CERTIFICATION (1) (2) Dated: November 22, 2011 Trung Tri Doan Chairman and Chief Executive Officer EX-32.1 7 a2206476zex-32_1.htm EX-32.1] [QuickLinks -- Click here to rapidly navigate through this document CERTIFICATION (1) (2) Dated: November 22, 2011 David Young Chief Financial Officer EX-32.2 8 a2206476zex-32_2.htm EX-32.2]