In 1998, the United States Department of Justice filed an antitrust lawsuit against Microsoft Corporation in the United States District Court for the District of Columbia.

Verified by Lenz · Jun 22, 2026

The Short Version

Official Justice Department records confirm that the United States filed an antitrust lawsuit against Microsoft on May 18, 1998, in the U.S. District Court for the District of Columbia. Later court documents and appellate records are consistent with that filing history. Parallel state lawsuits were separate and do not change the accuracy of the federal claim.

Caveats

Some sources discuss separate Microsoft litigation from 1998; those cases should not be confused with the May 18 antitrust filing.
State attorneys general filed parallel actions, but that does not negate the Justice Department's own complaint.
Wikipedia and secondary summaries are unnecessary here because primary DOJ records already establish the facts.

The Receipts

#223: 05-18-98 - JUSTICE DEPARTMENT FILES ANTITRUST SUIT AGAINST MICROSOFT FOR UNLAWFULLY MONOPOLIZING COMPUTER SOFTWARE MARKETS
Department of JusticeMay 18, 1998
Antitrust Division | U.S. V. Microsoft: Proposed Findings Of Fact - Department of Justice
Department of JusticeSep 19, 2023
Antitrust Division | U.S. V. Microsoft: Court's Findings Of Fact
Department of JusticeJul 26, 2018
Final Judgment : U.S. V. Microsoft Corporation; State Of New York, Et Al. V. Microsoft Corporation
Department of JusticeAug 14, 2015
United States v. Microsoft Corp. - Wikipedia
Wikipedia
United States Sues Microsoft | Law | Research Starters - EBSCO
EBSCO
U.S. v. Microsoft Corp., 253 F.3d 34 (D.C. Cir. 2001) - Justia Law
Justia Law
The Microsoft Antitrust Case | Stanford Graduate School of Business
Stanford Graduate School of Business
UNITED STATES v. MICROSOFT CORPORATION (1998) - FindLaw Caselaw
FindLaw CaselawJun 23, 1998

Filed Under

Microsoft CorporationUnited States Department of JusticeUnited States District Court For The District Of Columbia