William II of Poitiers

William II of Poitiers (31 January 1202 – c. 1227) was the only son and heir of Aymar II, count of Valentinois. In 1217 his father made peace with Simon de Montfort during the Albigensian Crusade and promised William to Simon's daughter Amicie, but the marriage never took place.

Around 1224 he married Flotte de Royans, heiress of Saint-Nazaire-en-Royans, who bore his successor Aymar III. He died before his father, leaving a disputed guardianship over the infant heir.