Sir William Vernon of Haddon (c. 1418/1419 – 30 June 1467) was an English landowner, politician, and soldier who held the posts of Treasurer of Calais and Knight-Constable of England.

William Vernon was born into a wealthy gentry family, very prominent in Cheshire and Derbyshire.

His father, Sir Richard Vernon, was Speaker of the House of Commons and Treasurer of Calais.

His mother, Benedicta, was the daughter of Sir John Ludlow of Hodnet, Shropshire.

The eldest son, Henry, became a powerful figure in his own right, as Controller of the household to Arthur, Prince of Wales.