Hildegar (also Hildiger or Hildeger; died 8 August 753) was the bishop of Cologne from 750. Probably of noble birth, he was a supporter of the Carolingians, who displaced the Merovingians in 751. After the appointment of Eoban to the diocese of Utrecht by the missionary bishop Boniface, Hildegar claimed metropolitan rights over the see. Boniface denied the charge in a letter to Pope Stephen II, although Marco Mostert has indicated that Boniface's narrative and arguments are flawed, if not outright lies.