William III of Aquitaine (915 – April 3, 963), nicknamed Tête d'Étoupe (Towhead) was William II of Poitou Count of Poitiers and Duke of Aquitaine from 935 to his death.
William was son of Ebalus of Aquitaine and Emiliene. He married Gerloc of Normandy (renamed Adele), daughter of Rollo of Normandy. They had at least two children: Adelaide, who married king Hugh I of France (Hugh Capet) and William, the heir.