William III of Aquitaine (c. 915 – April 3, 963) became the Duke of Aquitaine and Count of Poitiers in 935. He was the son of Ebalus of Aquitaine.
William's nickname was Towhead.
William was married to Adela of Normandy. He was the father of Adelaide of Aquitaine, who became Queen of France when she married Hugh Capet. He was succeeded by his son, William IV of Aquitaine.