EXHIBIT 5.1

December 10, 2010

SemiLEDs Corporation

3F, No. 11 Ke Jung Rd., Chu-Nan Site,

Hsinchu Science Park, Chu-Nan 350,

Miao-Li County, Taiwan, R.O.C.

Registration Statement on Form S-8

Ladies and Gentlemen:

At your request, we are rendering this opinion in connection with the proposed issuance of up to 3,152,402 shares of common stock, par value $0.0000056 per share (the “Shares”), of SemiLEDs Corporation, a Delaware corporation (the “Company”), pursuant to the Company’s 2005 Equity Incentive Plan (the “2005 Plan”) and 2010 Equity Incentive Plan (the “2010 Plan” and together with the 2005 Plan, the “Plans”) and pursuant to a Registration Statement on Form S-8 (the “Registration Statement”).

We have examined instruments, documents, and records which we deemed relevant and necessary for the basis of our opinion hereinafter expressed. In such examination, we have assumed the following: (a) the authenticity of original documents and the genuineness of all signatures; (b) the conformity to the originals of all documents submitted to us as copies; and (c) as to facts material to the opinion expressed herein, we have relied on certificates or comparable documents of the officers and representatives of the Company.

Based upon the foregoing examination and in reliance thereon, we are of the opinion that the Shares to be issued by the Company pursuant to the Plan have been duly authorized by all necessary corporate action of the Company and, when issued and sold as described in the Plans and Registration Statement, will be validly issued, fully paid and non-assessable.

In rendering this opinion, we have assumed that (i) the Registration Statement becomes and remains effective during the period when the Shares are offered, issued and sold, (ii) the Shares to be sold are issued in accordance with the terms of the Plans, (iii) the Company receives the full consideration for the Shares as stated in the Plans, (iv) the per share consideration for each Share includes payment of cash or other lawful consideration at least equal to the par value of the Company’s common stock, and (v) all applicable securities laws are complied with.

We hereby consent to the filing of this opinion as an exhibit to the above-referenced Registration Statement and to the use of our name wherever it appears in said Registration Statement, including any prospectus constituting a part thereof, as originally filed or as subsequently amended or supplemented. In giving such consent, we do not consider that we are “experts” within the meaning of such term as used in the Securities Act of 1933, as amended, or the rules and regulations of the Securities and Exchange Commission issued thereunder, with respect to any part of the Registration Statement, including this opinion as an exhibit or otherwise.

	Very truly yours,

	/s/ Orrick, Herrington and Sutcliffe LLP