William
- See William (name) for information about the name.
Royalty
- William of Albania, reigning king/prince
- King William I of Bimbia, king of the Isubu
- King William II of Bimbia, son of above
- King William I of England (William the Conqueror, William the Bastard)
- King William II of England
- King William III of England (Prince William III of Orange, King William II of Scotland, William of Orange)
- Emperor William I of Germany
- Emperor William II of Germany
- William I, Count of Holland (see also William of Holland)
- William II, Count of Holland
- William III, Count of Holland
- William IV, Count of Holland
- William V, Count of Holland
- William VI, Count of Holland
- King William I of the Netherlands
- King William II of the Netherlands
- King William III of the Netherlands
- Prince William I of Orange (William the Silent)
- Prince William II of Orange
- Prince William III of Orange (King William III of England)
- Prince William IV of Orange
- Prince William V of Orange
- Count William of Poitiers
- King William I of Scotland (William the Lion)
- King William II of Scotland (King William III of England)
- King William I of Sicily
- King William II of Sicily
- King William III of Sicily
- King William IV of the United Kingdom
- Prince William of Wales
- Prince William II Villehardouin
- Duke William IV "The Rich" of Cleves
- William, Archbishop of Mainz
- William, Count of Poitiers
Philosophers, theologians, and saints
- William of Auxerre (d. 1231), theologian
- William Jefferson Clinton (b 194?), saint
- William of Champeaux (1070 - 1121), theologian
- William de Corbeil, English bishop
- William of Conches (1080 - 1154), philosopher
- William of Gellone, saint
- William of Mainz, German bishop
- William of Malmesbury, English historian
- William of Moerbeke (1215 - 1286)
- William of Norwich (1132 - 1144), saint and supposed martyr
- William of Ockham, English friar, philosopher and originator of Occam's Razor
- William of Sodor and Man, 11th Bishop of Sodor and Man
- William de la Pole, English nobleman
- William of St. Carilef, English bishop
- William of St. Thierry (1085 - 1148), theologian
- William of Tyre, Bishop in the Holy Land
- William Waynflete (1395 - 1486), bishop
- William of Wied, German nobleman
- William of Wykeham, English bishop
- Saint William of York, English bishop
Others:
- William, bishop of Zaragoza (Spain) in 1137.
Also, will.i.am of The Black Eyed Peas appears to come from "William".