William III may refer to:
- William III of Aquitaine (915–963)
- William III of Toulouse (died 1037)
- William III of Provence (died after 1037)
- William III of Montferrat (970–1042)
- William III of Angoulême (1084–1118)
- William III of Ponthieu (c. 1095–1172)
- William III of Sicily (1190–1198)
- William III of Dampierre (1224–1251)
- William III of Cagliari (ruled 1256–1258)
- Sir William Douglas the Hardy (died c. 1298)
- William I, Count of Hainaut or William III of Holland (1286–1337)
- Uilleam III, Earl of Ross (died 1370)
- William I, Duke of Bavaria or William III of Hainaut (1330–1389)
- William III, Duke of Bavaria (1375–1435)
- William III, Duke of Luxembourg (1425–1482)
- William III of England or William III of Orange or William II of Scotland (1650–1702)
- William III of the Netherlands (1817–1890)
Famous quotes containing the words william and/or iii:
“With wonderful deathless ditties
We build up the world’s great cities,”
—Arthur William Edgar O’Shaughnessy (1844–1881)
“Knavery seems to be so much a the striking feature of its inhabitants that it may not in the end be an evil that they will become aliens to this kingdom.”
—George III (1738–1820)