The Pocumtuck, also Pocomtuc or Deerfield Indians, are a Native American tribe formerly inhabiting western Massachusetts, especially around the confluence of the Deerfield and Connecticut Rivers in Franklin County.

Their territory also includes parts of Hampden and Hampshire County, as well as portions of Connecticut and Vermont.

Their principal village, also known as Pocumtuck, is in the vicinity of current Deerfield, Massachusetts.

Their language, now extinct, is an R-dialect of the Algonquian language family, most likely related to the Wappinger and nearby Mahican tribes of the Hudson River Valley.