William Windsor may refer to:
- Prince William of Gloucester (1941–1972), grandson of King George V
- William, Prince of Wales (born 1982), elder son of King Charles III
- William de Windsor (c. 1325–1384), English feudal lord
- William Windsor, 2nd Baron Windsor (1498–1558), MP for Chipping Wycombe in 1529
- Bobby Windsor (born 1948), British rugby union footballer
- William Windsor (goat) (fl. 2001–2009), known as "Billy", a military mascot goat