Gaheris (Old French: Gaheriet or Gaheriez) is a character in the Arthurian legend, a nephew of King Arthur and a Knight of the Round Table. As the third son of Arthur's sister or half-sister Morgause and her husband Lot, King of Orkney and Lothian, he is the younger brother of Gawain and Agravaine, and the older brother of Gareth and half-brother of Mordred.