William Sampson may refer to:
- William Sampson (author) (1959-2012), a Canadian/British citizen arrested and tortured by the Saudi government between 2000 and 2003
- William Sampson (judge), Chief Justice of the Kentucky Supreme Court during the Civil War
- William Sampson (lawyer) (1764–1836), a United Irishmen lawyer exiled to the United States
- William Sampson (playwright), collaborated with Gervase Markham
- William Harkness Sampson, Methodist minister and educator, founder of Lawrence University
- William T. Sampson (1840–1902), American admiral and commander in the Spanish-American War