Sir William Williams

• Sir William Williams, 1st Baronet, of Vaynol
• Sir William Williams, 1st Baronet, of Tregullow, see Williams family of Caerhays and Burncoose
• Sir William Williams, 1st Baronet, of Gray's Inn, Welsh lawyer and politician, speaker of the House of Commons
• Sir William Williams, 1st Baronet, of Kars, British military leader of the Victorian era, Member of Parliament for Calne
• Sir William Williams, 2nd Baronet, of Clapton Member of Parliament for New Shoreham
• Sir William Williams, 2nd Baronet, of Gray's Inn, Welsh politician, Member of Parliament for Denbigh
• Sir William Emrys Williams, British educationalist and Editor-in-Chief of Penguin Books, 1936–1965
• Sir Thomas Williams (Warrington MP), British Labour Co-operative politician, Member of Parliament for Hammersmith South, Barons Court and Warrington