William Addison may refer to:
- William Addison (physician) (1803âÂÂ1881), British physician
- William Addison (VC) (1883âÂÂ1962), holder of the Victoria Cross
- William Addison, 4th Viscount Addison (born 1945), British Conservative peer
- William Addison (chess player) (1933âÂÂ2008), American chess master
- William Fountaine Addison (1817âÂÂ1893), clergyman, Canon of Gibraltar, father of Robert Brydges Addison
- William Grylls Addison (1853âÂÂ1904), English landscape painter, brother of Robert Brydges Addison
- William Wilkinson Addison (1905âÂÂ1992), English historian and jurist