Sir William Mountfort (died 6 December 1452) was an English MP.
He held a number of commissions in both Warwickshire and neighbouring counties.
He was appointed High Sheriff of Warwickshire and Leicestershire for 1431–32, 1441–42 and 1450–51 and was Captain of Honfleur, Normandy during 1438.
He was elected to Parliament as the MP for Warwickshire in 1410 and returned a further seven times until 1450.
He was married twice:firstly Margaret or Margery, the daughter and heiress of Sir John Pecche of Hampton in Arden, with whom he had 6 sons and 2 daughters and secondly Joan, the daughter of William Alderwich of Aldridge, Staffordshire and the widow of William Brokesby of Shoby, Leicestershire, with whom he had a further son, Edmund.