Windham is a town in Windham County, Connecticut, United States. It contains the former city of Willimantic as well as the communities of Windham Center, North Windham, and South Windham. Willimantic, an incorporated city since 1893, was consolidated with the town in 1983. The town is part of the Southeastern Connecticut Planning Region. The population was 24,428 at the 2020 census.

Windham County is one of the eight historical counties in the U.S. state of Connecticut, located in its northeastern corner. As of the 2020 census, the population was 116,418, making it the least populous county in Connecticut. It forms the core of the region known as the Quiet Corner. Windham County is included in the Worcester, MA-CT Metropolitan Statistical Area, which is also included in the Boston-Worcester-Providence, MA-RI-NH-CT Combined Statistical Area. The entire county is within the Quinebaug and Shetucket Rivers Valley National Heritage Corridor, as designated by the National Park Service.