6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of January 2025

Commission File Number: 001-15092

TURKCELL ILETISIM HIZMETLERI A.S.

(Translation of registrant’s name into English)

Aydınevler Mahallesi İnönü Caddesi No:20

Küçükyalı Ofispark

34854 Maltepe

Istanbul, Türkiye

(Address of Principal Executive Offices)

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

x Form 20-F  ¨ Form 40-F

Enclosure: A press release dated January 24, 2025 announcing the registrant’s completion of debt instrument issuance.

Istanbul, January 24, 2025

Announcement Regarding Completion of DebtInstrument Issuance

The sale process of the sustainable bond issuance of our Company with a nominal amount of USD 500 million, 7-year maturity, a redemption date of 24.01.2032, a fixed annual coupon rate of 7.65%, and a sales price of 100% of the nominal value, to qualified investors abroad was completed on January 24, 2025. The subscription agreement for the issuance was signed on January 22, 2025. The sustainable bond is listed on the Irish Stock Exchange (Euronext Dublin). The proceeds were transferred to our Company's accounts.

Notification Regarding Issue of Capital Market Instrument (DebtInstrument)

1

Redemption Plan of Capital Market Instrument Sold

** Ifthe payment date is not a business day, it shall mean the following business day

Issuer Rating Note

Capital Market Instrument Rating Note

Disclaimer

This press release does not constitute anoffer to sell, or a solicitation of offers to purchase or subscribe for securities in the United States or any other jurisdiction inwhich such offer or solicitation would be unlawful. The securities referred to herein have not been and will not be registered underthe U.S. Securities Act of 1933, as amended (the “Securities Act”), and may not be offered, sold or delivered within theUnited States or to or for the benefit of, U.S. persons (as defined in Regulation S under the Securities Act) absent registration oran applicable exemption from the registration requirements of thes Securities Act. This press release is being issued pursuant to andin accordance with Rule 135c under the Securities Act.

For more information:

Turkcell Investor Relations

investor.relations@turkcell.com.tr

Tel: + 90 212 313 1888

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SIGNATURES

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