Sir William Constantine (1612–1670) was an English politician who sat in the House of Commons of England from 1640 to 1643.
He supported the Royalist side in the English Civil War Constantine was of an ancient and respectable family of Poole, Dorset.
He was re-elected in November 1640 for the Long Parliament but was disabled in September 1643 for his support of the king.
His estate was sequestered by the house and he was sent to London for imprisonment in the King's Bench prison.
[3] He was displaced from his position as recorder by the commissioners under the corporation act on 17 October 1662.