Opinion of Sullivan & Cromwell LLP

Exhibit 5.1

January 11, 2019

Nomura Holdings, Inc,

9-1, Nihonbashi 1-chome,

Chuo-ku, Tokyo 103-8645,

Japan.

Ladies and Gentlemen:

In connection with the registration under the Securities Act of 1933 (the “Act”) of an unspecified initial principal amount or number of senior debt securities (the “Securities”) of Nomura Holdings, Inc., a Japanese corporation (the “Company”), we, as your special counsel, have examined such corporate records, certificates and other documents, and such questions of law, as we have considered necessary or appropriate for the purposes of this opinion.

Upon the basis of such examination, it is our opinion that, when (i) the registration statement on Form F-3 (the “Registration Statement”) has become effective under the Act, (ii) in the case of Securities to be issued pursuant to the senior debt indenture to be entered into between the Company and Citibank, N.A., the form of which is included as an exhibit to the Registration Statement (the “Citibank Indenture”), the Citibank Indenture has been duly executed and delivered, (iii) the terms of the Securities and of their issuance and sale have been duly established in conformity with the Amended and Restated Senior Debt Indenture between the Company and the Deutsche Bank Trust Company Americas dated as of January 12, 2011 (the “Deutsche Bank Indenture”, and, together with the Citibank Indenture, the “Indentures”) or the Citibank Indenture, as applicable, so as not to violate any applicable law or result in a default under or breach of any agreement or instrument binding upon the Company and so as to comply with any requirement or restriction imposed by any court or governmental body having jurisdiction over the Company, and (iv) the Securities have been duly executed and authenticated in accordance with the applicable Indenture and issued and sold as contemplated in the Registration Statement, and assuming the Securities will constitute valid and legally binding obligations of the Company under the laws of Japan, the Securities will constitute valid and legally binding obligations of the Company, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles.

In rendering the foregoing opinion, we are not passing upon, and assume no responsibility for, any disclosure in any registration statement or any related prospectus or other offering material relating to the offer and sale of the Securities.

We note that, as of the date of this opinion, a judgment for money in an action based on a Security denominated in a foreign currency or currency unit in a Federal or state court in the United States ordinarily would be enforced in the United States only in United States dollars. The date used to determine the rate of conversion of the foreign currency or currency unit in which a particular Security is denominated into United States dollars will depend upon various factors, including which court renders the judgment. Under Section 27 of the New York Judiciary Law, a state court in the State of New York rendering a judgment on a Security would be required to render such judgment in the foreign currency or currency unit in which the Security is denominated, and such judgment would be converted into United States dollars at the exchange rate prevailing on the date of entry of the judgment.

The foregoing opinion is limited to the Federal laws of the United States and the laws of the State of New York, and we are expressing no opinion as to the effect of the laws of any other jurisdiction. With respect to all matters of Japanese law, we note that you have received the opinion, dated January 11, 2019, of Anderson Mori & Tomotsune.