Sir Agravain /æɡræveɪn/ (sometimes spelled Agravaine) is a Knight of the Round Table in Arthurian Legend. In Chrétien de Troyes, the Vulgate, Post-Vulgate cycles and Thomas Malory's Le Morte d'Arthur, he is the second eldest son of King Lot of Orkney with Anna/Morgause/Morgan (Arthur's sister), thus nephew of King Arthur, and brother to Sir Gawain, Gaheris, and Gareth, and half-brother to Mordred.
He is generally portrayed as handsome, and a capable fighter, and participates in a number of adventures early in the Vulgate Cycle, sometimes even doing heroic deeds. In Sir Gawain and the Green Knight, where he is called "Agravain of the Hard Hand", he is named in a list of respectable knights; this, combined with his unobjectionable depiction in Chrétien de Troyes' Perceval, suggests his reputation might not have been very negative prior to the Vulgate.