Algonquian (Algonquian languages)-speaking North American Indian group that originally occupied the central plateau of what is now the U.S. state of Massachusetts and extended into what are now northern Rhode Island and Connecticut. Their subsistence was based on hunting, fishing, and the cultivation of corn (maize); they moved seasonally between fixed sites to exploit these food resources. The Nipmuc were divided into territorial bands, or groups of related families living in one or more villages; each village was ruled by a sachem, or chief. The many Nipmuc villages were not united politically; rather than forming a pan-Nipmuc alliance, each village allied with its more powerful neighbours, such as the Massachuset, Wampanoag, Narragansett (Narraganset), and Mohegan.

By 1674 New England missionaries had established seven villages of Christian converts, but in the following year most of the Nipmuc joined King Philip (King Philip's War) and other hostile tribes in an attempt to force the colonists to leave New England (see King Philip's War). At the close of the war they fled to Canada or to the Mohican and other tribes on the Hudson River.

Early 21st-century population estimates indicated approximately 1,500 individuals of Nipmuc descent.