Waitstill Winthrop (27 February 1641/42 – 7 November 1717) was a colonial magistrate, military officer, and politician of New England.
Wait Winthrop, born 27 February 1641/42 in Boston, the capital of the Massachusetts Bay Colony, was the son of John Winthrop the Younger and the grandson of John Winthrop, a leading founder of the Massachusetts Bay Colony. Named Waitstill at birth, he preferred the shortened name "Wait". He was chief judge of the Massachusetts superior court (the highest court in the Province of Massachusetts Bay), and was a long-time councilor and contender for the governorship of Massachusetts. During King Philip's War in the 1670s and King William's War in the 1690s, he led the Massachusetts provincial militia. Politically populist, he worked against royal governors, especially Joseph Dudley, and sought the restoration of the first Massachusetts charter. In 1692 he was appointed by Governor Sir William Phips as one of the magistrates of the Court of Oyer and Terminer that heard the Salem witch trials. That same year he was elected to membership in the Military Company of Massachusetts and was also elected as captain of the Company in June.
When the provincial courts were organized under the new charter of the Province of Massachusetts Bay, Winthrop was one of the initial appointees as an associate justice of the Superior Court of Judicature, as the province's highest court was known. He held this position until the death of chief justice and acting governor William Stoughton, at which time the governor's council appointed him to be chief justice. Political forces allied to him were preparing to travel to London to lobby on his behalf for the position of governor when it was learned that Joseph Dudley had received the appointment. Winthrop then tendered his resignation as chief justice. In 1708 Dudley reappointed him to be chief justice, a position he held until his death in 1717.