William, Count of Évreux

William of Évreux or William d'Évreux (French: Guillaume d'Évreux; died 18 April 1118) was a member of the House of Normandy who played an influential role during the Norman conquest of England, one of the few Norman aristocrats documented to have been with William I at Hastings. He was the count of Évreux (Latin: Willelmus Comes Ebroicensis; ruled c. 1067–1118) in Normandy as well as additional lands and expanded his holdings by consenting to the marriage of his young ward and niece Bertrade to Fulk the Rude of Anjou, whose support against the Manceaux rebels was important for William's liege Robert Curthose. A feud between William's wife Helvise or Heloise of Nevers (died 1114) and Isabel of Conches, the wife of Raoul II of Tosny, led to open war between the two men. Helvise also governed Évreux in William's infirm old age until her own death. Having no children of his own, William was succeeded at Évreux by his sister's son Amaury de Montfort.