The Sts'ailes are a First Nations people in the Lower Mainland of the Canadian province of British Columbia. They are a Halqemeylem-speaking people but are distinct historically and politically from the surrounding Sto:lo peoples. Their band government is the Chehalis First Nation, and is located at the Indian Reserve community of Chehalis, British Columbia, which is named after them and is located on the Harrison River between the towns of Mission and Agassiz.
Their name means "beating heart". Their usual English name, Chehalis, is identical to that of the much more numerous Chehalis people of southern Puget Sound in Washington. By Sts'ailes tradition, the southern Chehalis were separated from their homeland as a consequence of the Great Flood.