The Wangunk or Mattabesec were an Indigenous people from central Connecticut. They were a subdivision of the Wappinger people, a Munsee-speaking people. The Wangunk settled along the Connecticut River.

Prior to English arrival, the Wangunk had three major settlements along the Connecticut River, in the areas of the present-day towns of Portland, Middletown, and Wethersfield. They also used lands in other parts of what were later organized by English settlers as Middlesex and Hartford counties.

There are no Wangunk state-recognized tribes or federally recognized tribes,

Wangunk descendants, scholars, and local government have made public statements affirming the Wangunk peoples' continuance and highlighting their historic erasure.

The Wangunk were also called Wangums and Wongunk.

Anthropologist John Reed Swanton called them the Mattabesec.

Their name has also been written as Mattabessett or Mattabesch, but Wangunk is the name used by scholars and by contemporary Wangunk descendants.

Swanton writes that the Mattabesec were the most important band of Wappinger people, who spoke an Eastern Algonquian language.