William Borthwick may refer to:
William Borthwick (Canadian politician) (1848–1928), mayor of Ottawa, 1895–1896 Bill Borthwick (1924–2001), Australian politician William Borthwick, 1st Lord Borthwick (died 1458), Scottish peer and ambassador William Borthwick, 2nd Lord Borthwick (died 1483), Scottish ambassador to England William Borthwick, 3rd Lord Borthwick (died 1503), Scottish nobleman and ambassador William Borthwick, 4th Lord Borthwick (died 1542), Scottish nobleman William Borthwick (Dorset politician) (1879–1956), British Army Captain and barrister William Jason Maxwell Borthwick (1910–1998), British barrister and Royal Naval Volunteer Reserve officer William Borthwick (surgeon) (1641–1689), Scottish surgeon
See also Borthwick (surname)