6-K

UNITED STATES

SECURITIES ANDEXCHANGE COMMISSION

Washington, D.C.20549

FORM 6-K****

REPORTOF FOREIGN PRIVATE ISSUER

PURSUANTTO RULE 13a-16 OR 15d-16 OF THE

SECURITIESEXCHANGE ACT OF 1934

For the month of December, 2024.

Commission FileNumber: 001-38763

MILLICOM INTERNATIONALCELLULAR S.A.

(Exact Name ofRegistrant as Specified in Its Charter)

148-150, Boulevardde la Pétrusse

L-2330 Luxembourg

Grand Duchy ofLuxembourg

(Address of principalexecutive office)

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

Form 20-F x Form 40-F ¨

MILLICOM INTERNATIONAL CELLULAR S.A.

INDEX TO FURNISHED MATERIAL

Item

_____

Item1

Millicom(Tigo) share repurchase activity

Luxembourg,December 9, 2024 - Pursuant to the share repurchases announced on November 29, 2024, Millicom repurchased 277,905 of its Swedish Depository Receipts (SDRs) between December 2, 2024, and December 6, 2024, as detailed in the table below.

*Excluding commissions

All purchases were carried out on Nasdaq Stockholm by Citigroup Global Markets Limited on behalf of Millicom. Following the purchases, Millicom holds 868,951 treasury shares as of December 6, 2024. The total number of shares outstanding in Millicom is 172,096,305.

For information about all transactions carried out under the repurchase program, refer to Nasdaq Stockholm’s website:

https://www.nasdaq.com/european-market-activity/news/corporate-actions/repurchase-of-own-shares

-END-

Forfurther information, please contact

AboutMillicom

Millicom (NASDAQ U.S.: TIGO, Nasdaq Stockholm: TIGO_SDB) is a leading provider of fixed and mobile telecommunications services in Latin America. Through our TIGO® and Tigo Business® brands, we provide a wide range of digital services and products, including TIGO Money for mobile financial services, TIGO Sports for local entertainment, TIGO ONEtv for pay TV, high-speed data, voice, and business-to-business solutions such as cloud and security. As of September 30, 2024, Millicom, including its Honduras Joint Venture, employed approximately 15,000 people, and provided mobile and fiber-cable services through its digital highways to more than 46 million customers, with a fiber-cable footprint of about 14 million homes passed. Founded in 1990, Millicom International Cellular S.A. is headquartered in Luxembourg.

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.

Date: December 10, 2024