FORM 6-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Private Issuer

Pursuant to rule 13a-16 or 15d-16 of

The Securities Exchange Act of 1934

For the month of August, 2015

National Bank of Greece S.A.

(Translation of registrant’s name into English)

86 Eolou Street, 10232 Athens, Greece

(Address of principal executive offices)

[Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.]

Form 20-F x  Form 40-F o

[Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to rule 12g3-2(b) under the Securities Exchange Act of 1934.]

Yes o  No x

[If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82-       ]

27/8/2015

PRESS RELEASE

The Board of Directors of National Bank of Greece, during today’s meeting, following a relevant proposal by the Bank’s HR Committee, decided to assign Yiannis Kyriakopoulos the position of Bank and Group CFO, effective as of the 4th of September 2015.

2

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

3