William of the United Kingdom most commonly refers to:
William IV (1765–1837; ) William, Prince of Wales (born 1982), heir apparent to Charles III
William of the United Kingdom or William of Great Britain may also refer to:
Prince William, Duke of Cumberland (1721–1765), third and youngest son of George II Prince William Henry, Duke of Gloucester and Edinburgh (1743–1805), grandson of George II and brother of George III Prince William Frederick, Duke of Gloucester and Edinburgh (1776–1834), son-in-law of George III Prince William of Gloucester (1941–1972), grandson of George V
See also , lists princes outside of British Isles named William Princess William (disambiguation), lists spouses of British princes named William William and Catherine (disambiguation) William of England (disambiguation), lists kings named William in one predecessor state of Great Britain William the Lion ( – 1214; ), also known as William I, King of Scots (another predecessor state of Great Britain)