6-K

UNITED STATES

SECURITIES AND EXCHANGE 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 September, 2022

Commission FileNumber: 001-38763

MILLICOM INTERNATIONAL CELLULAR S.A.

(Exact Name ofRegistrant as Specified in Its Charter)

2, Rue du FortBourbon,

L-1249 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 ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):

Yes ¨              No x

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):

Yes ¨               No x

MILLICOM INTERNATIONAL CELLULAR S.A.

INDEX TO FURNISHED MATERIAL

Item

______

1. Press release dated September 20, 2022

Item 1

Notificationof share transaction by Millicom Executive

Luxembourg,September 20, 2022 – Millicom International Cellular S.A. (NASDAQ: TIGO) announces that on September 19, 2022, its Chief Information and Technology Officer, Mr. Xavier Rocoplan, purchased 57,633 Millicom shares in the open market at an average price of $12.38 per share. Mr. Rocoplan now directly owns 97,974 shares.

-END-

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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 June 30, 2022, Millicom employed approximately 20,000 people and provided mobile and fiber-cable services through its digital highways to around 50 million customers, with a fiber-cable footprint of close to 13 million homes passed. Founded in 1990, Millicom International Cellular S.A. is headquartered in Luxembourg. For more information, visit: millicom.com. Connect with Millicom on Twitter, Instagram, Facebook, and LinkedIn.

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: September 20, 2022