American cultural anthropologist known for his work on the Algonquin Indian tribes of the eastern United States.

Speck studied under Franz Boas at Columbia University. He founded the anthropology department at the University of Pennsylvania and was its chairman for much of his life.

Speck attempted, as did others of the period, to preserve and analyze fragments of information about the changes faced by indigenous peoples who had been colonized. From only scattered remnants of ritual and lore, Speck was able in some cases to reconstruct extensive information on the historic culture of the Delaware and other tribes. He pioneered investigations in ethnoscience and ethnomusicology and gathered a large body of native folklore. He is remembered for the respect he enjoyed in Indian communities.