William FitzWilliam
William FitzWilliam or Fitzwilliam may refer to:
- William Fitzwilliam , protégé of Cardinal Wolsey
- William FitzWilliam, 1st Earl of Southampton, English courtier
- William Fitzwilliam
- William Fitzwilliam , MP
- William FitzWilliam , Lord Deputy of Ireland
- William FitzWilliam, 2nd Baron FitzWilliam, English politician
- William FitzWilliam, 3rd Viscount FitzWilliam, Irish nobleman
- William Fitzwilliam, 3rd Earl Fitzwilliam, British peer
- William Fitzwilliam, 4th Earl Fitzwilliam, British Whig statesman
- William Wentworth-Fitzwilliam, 6th Earl Fitzwilliam, British peer and Liberal politician
- William Wentworth-Fitzwilliam, 7th Earl Fitzwilliam, British Army officer, politician and aristocrat
- William Fitzwilliam, 1st Earl Fitzwilliam, English nobleman, politician, and peer
- William Fitzwilliam, Viscount Milton, British Member of Parliament for Malton