Goreu fab Custennin (also spelled as Gorau) is a hero of Welsh and early Arthurian mythology, the son of Custennin, and cousin to Arthur, Culhwch and Saint Illtud through their grandfather Amlawdd Wledig. He is a significant character in the Middle Welsh Arthurian tale Culhwch and Olwen, and also appears in a number of other medieval texts. His name may be derived from Gorneu; "of Cornwall."