William Rainsborough (1587? – 1642) was an English Captain and Vice-Admiral in the Royal Navy, English ambassador to Morocco and politician who sat in the House of Commons from 1640 to 1642. On the orders of Charles I of England, Rainsborough led a successful naval expedition against the Barbary corsairs of Salé in June 1637. His exploits were hailed in a court masque designed by Inigo Jones For his services to end white slavery Rainsborough was offered a hereditary knighthood, which he declined, and was presented with a Gold Chain and Medal by Charles I.