Wompatuck (died 1669), known to English settlers as Josiah Sagamore, was a leader of the Mattakeesett tribe of the Massachusetts Indians. He was the son of Massachusett sachem Chickatawbut. His name meant "snow goose" in the Wampanoag language.
Wompatuck was an early friend of European settlers. He sold the British the land upon which the city of Boston, Massachusetts, was established in 1629. After an harsh attack on his tribe by the Hodenesaunee Iroquois in 1665, he organized a great expedition for retaliation, involving several Massachusett tribes with 600 or 700 warriors, against Mohawk's capital, Gandaouaguè. Coming back to New England, his column was ambushed and he was slain in 1669 when he led a force of his warriors in an attack upon the Mohawks.
The United States Navy harbor tug USS Wampatuck (YT-337), later YTB-337, in commission from 1942 to 1946, was named for him. Wompatuck State Park located in Hingham, Massachusetts is also named after him. Also, he is honored by the town of Braintree in calling their sports teams the Wamps.