Exhibit 5.1

	CONYERS DILL & PEARMAN LIMITED
	Clarendon House, 2 Church Street
	Hamilton HM 11, Bermuda
	Mail: PO Box HM 666, Hamilton HM CX, Bermuda
	T +1 441 295 1422
	conyers.com

18 May 2020

Kiniksa Pharmaceuticals, Ltd.

Clarendon House

2 Church Street

Hamilton HM 11

Bermuda

Dears Sirs

Re: Kiniksa Pharmaceuticals, Ltd. (the “Company”)

We have acted as special Bermuda legal counsel to the Company in connection with an offering to be made pursuant to the prospectus (the “Prospectus”, which term does not include any other document or agreement whether or not specifically referred to therein or attached as an exhibit or schedule thereto) comprised of a base prospectus included in a registration statement on Form S-3 (File No. 333-231910) (the “Registration Statement”, which term does not include any other document or agreement whether or not specifically referred to therein or attached as an exhibit or schedule thereto) declared effective by the U.S. Securities and Exchange Commission (the “Commission”) on June 10, 2019, as supplemented by the prospectus supplement dated May 13, 2020, relating to the registration under the U.S. Securities Act of 1933, as amended, (the “Securities Act”) of 2,400,000 of the Company’s common shares, par value US$0.000273235 each (“Common Shares”), such Common Sales to be sold pursuant to an underwriting agreement dated May 13, 2020 (the “Underwriting Agreement”) entered into between the Company and Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC and BofA Securities, Inc., as representatives (the “Representatives”) of the several underwriters named therein.

For the purposes of giving this opinion, we have examined a copy of the Registration Statement and the Prospectus. We have also reviewed the memorandum of association and the bye-laws of the Company (together, the “Constitutional Documents”), each certified by the Secretary of the Company on May 18, 2020, resolutions adopted at a meeting of its directors held on May 29, 2019 and on May 11, 2020 each as certified by the Secretary of the Company on May 18, 2019 (together, the "Resolutions") and such other documents and made such enquiries as to questions of law as we have deemed necessary in order to render the opinion set forth below.

We have assumed (a) the genuineness and authenticity of all signatures and the conformity to the originals of all copies (whether or not certified) examined by us and the authenticity and completeness of the originals from which such copies were taken; (b) that where a document has been examined by us in draft form, it will be or has been executed and/or filed in the form of that draft, and where a number of drafts of a document have been examined by us all changes thereto have been marked or otherwise drawn to our attention; (c) the accuracy and completeness of all factual representations made in the Registration Statement and the Prospectus, and any other documents reviewed by us; (d) that the Resolutions were passed at one or more duly convened, constituted and quorate meetings or by unanimous written resolutions, remain in full force and effect and have not been, and will not be, rescinded or amended; (e) that the Constitutional Documents will not be amended in any manner that would affect the opinions expressed herein; (f) that there is no provision of the law of any jurisdiction, other than Bermuda, which would have any implication in relation to the opinions expressed herein; (g) that the Company will have sufficient authorised capital to effect the issue of any of the Common Shares at the time of issuance; (h) that the Company’s Common Shares will be listed on an appointed stock exchange, as defined in the Companies Act 1981, as amended (the “Companies Act”), which includes the NASDAQ, at the time of the issuance of any Common Shares; and (i) that, upon the issue of any Common Shares, the Company will receive consideration for the issue price thereof which shall be equal to at least the par value thereof.

We have made no investigation of and express no opinion in relation to the laws of any jurisdiction other than Bermuda. This opinion is to be governed by and construed in accordance with the laws of Bermuda and is limited to and is given on the basis of, the current law and practice in Bermuda. This opinion is issued solely for your benefit and use in connection with the matter described herein and is not to be relied upon by any other person, firm or entity or in respect of any other matter.On the basis of and subject to the foregoing we are of the opinion that:

We hereby consent to (i) the filing of this opinion as an exhibit to the Company’s Current Report on Form 8-K filed on or about May 18, 2020 for incorporation by reference into the Registration Statement, and (ii) to the references to our firm under the caption “Legal Matters” in the Registration Statement. In giving such consent, we do not hereby admit that we are experts within the meaning of Section 11 of the Securities Act or that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the Rules and Regulations of the Commission promulgated thereunder.

Yours faithfully,

/s/ Conyers Dill & Pearman Limited

Conyers Dill & Pearman Limited

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