Exhibit



	Hogan Lovells US LLP 1735 Market Street, 23^rd Floor Philadelphia, PA 19103 T +1 267 675 4600 F +1 267 675 4601 www.hoganlovells.com

Exhibit 5.1

October 31, 2017

Board of Directors

Eleven Biotherapeutics, Inc.

245 First Street, Suite 1800

Cambridge, MA 02142

Ladies and Gentlemen:

We are acting as counsel to Eleven Biotherapeutics, Inc., a Delaware corporation (the “Company”), in connection with its registration statement on Form S-1, as amended (the “Registration Statement”), filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Act”), relating to the proposed public offering of up to 10,000,000 units (the “Units”) (each consisting of a share of common stock of the Company and a warrant to purchase one share of common stock), 11,500,000 shares of common stock of the Company, par value $0.001 per share (the “Shares”) and 11,500,000 warrants to purchase common stock (the “Warrants”) and the shares of common stock of the Company issuable from time to time upon exercise of the Warrants (the “Warrant Shares”); 10,000,000 pre-funded units (the “Pre-Funded Units”), each consisting of a pre-funded warrant to purchase one share of Common Stock (each, a “Pre-Funded Warrant” and collectively, the “Pre-Funded Warrants”) and one Warrant, and the shares of the Company’s Common Stock issuable from time to time upon exercise of the Pre-funded Warrants (the “Pre-Funded Warrant Shares”; and together with the Units, Shares, Warrants, Warrant Shares, Pre-Funded Units and Pre-Funded Warrants are collectively referred to herein as the “Securities”), all of which Securities are to be sold by the Company. The Securities will be sold pursuant to an Agreement between the Company and H.C. Wainwright & Co., LLC (the “Agreement”). As noted in the Registration Statement, for each Pre-Funded Unit sold, the number of Units sold will be decreased on a one-for-one basis. This opinion letter is furnished to you at your request to enable you to fulfill the requirements of Item 601(b)(5) of Regulation S‑K, 17 C.F.R. § 229.601(b)(5), in connection with the Registration Statement.

For purposes of this opinion letter, we have examined copies of such agreements, instruments and documents as we have deemed an appropriate basis on which to render the opinions hereinafter expressed. In our examination of the aforesaid documents, we have assumed the genuineness of all signatures, the legal capacity of all natural persons, the accuracy and completeness of the documents submitted to us, the authenticity of the original documents submitted to us, and the conformity to authentic original documents of the documents submitted to us as copies (including pdfs). As to all matters of fact, we have relied on the representations and statements of fact made in the documents so reviewed, and we have not independently established the facts so relied on. This opinion letter is given, and all statements herein are made, in the context of the foregoing.

This opinion letter is based as to matters of law solely on the Delaware General Corporation Law, as amended, and, as to the Warrants constituting valid and legally binding obligations of the Company, with respect to the laws of the State of New York. We express no opinion herein as to any other statutes, rules or regulations.

Based upon, subject to and limited by the foregoing, we are of the opinion that following (i) execution and delivery by the Company of the Agreement, (ii) effectiveness of the Registration Statement, (iii) issuance of the Securities pursuant to the terms of the Agreement, and (iv) receipt by the Company of the consideration for the Securities specified in the resolutions of the Board of Directors and the Pricing Committee of the Board of Directors:


(a)	the Securities will be duly authorized for issuance and, when issued, delivered and paid for in accordance with the terms of the Agreement, will be validly issued, fully paid and nonassessable;

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(b)

The Warrants and Pre-Funded Warrants will be duly authorized for issuance and, when issued and sold in accordance with the Agreement and duly executed and delivered by the Company to the purchasers thereof against payment therefor, will constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms, except as may be limited by bankruptcy, insolvency, reorganization, receivership, moratorium or other laws affecting creditors’ rights (including, without limitation, the effect of statutory and other law regarding fraudulent conveyances, fraudulent transfers and preferential transfers) and by the exercise of judicial discretion and the application of principles of equity, good faith, fair dealing, reasonableness, conscionability and materiality (regardless of whether the Warrants or Pre-Funded Warrants are considered in a proceeding in equity or at law); and


(c)	The Warrant Shares and Pre-Funded Warrant Shares will be duly authorized and, when issued and paid for in accordance with the provisions of the Warrants and Pre-Funded Warrants, as applicable, will be validly issued and be fully paid and nonassessable.

This opinion letter has been prepared for use in connection with the Registration Statement. We assume no obligation to advise of any changes in the foregoing subsequent to the effective date of the Registration Statement.

We hereby consent to the filing of this opinion letter as Exhibit 5.1 to the Registration Statement and to the reference to this firm under the caption “Legal Matters” in the prospectus constituting a part of the Registration Statement. In giving this consent, we do not thereby admit that we are an “expert” within the meaning of the Act.

Very truly yours,

/s/ Hogan Lovells US LLP

HOGAN LOVELLS US LLP