Ywain, also called Owain, Yvain, Ewain or Uwain, is a Knight of the Round Table in the Arthurian legend.

Ywain may also refer to:

Owain mab Urien, historical figure Ywain the Bastard, another Knight of the Round Table Yvain, the Knight of the Lion, a 12th-century romance by Chrétien de Troyes Owain, or the Lady of the Fountain, a Welsh adaptation of Chrétien's Yvain 9501 Ywain, minor planet Yvaine, a fictional character in Stardust

See also Owain, name