Ywain, also known as Yvain and Owain among other spellings, is a Knight of the Round Table in Arthurian legend, wherein he is often the son of King Urien of Gorre and either the enchantress Modron or the sorceress Morgan le Fay. The historical Owain mab Urien, on whom the literary character is based, was the king of Rheged in Great Britain during the late 6th century.

The Knights of the Round Table are the legendary knights of the fellowship of King Arthur that first appeared in the Matter of Britain literature in the mid-12th century. The Knights are an order dedicated to ensuring the peace of Arthur's kingdom following an early warring period, entrusted in later years to undergo a mystical quest for the Holy Grail. The Round Table at which they meet is a symbol of the equality of its members, who range from sovereign royals to minor nobles.