William Adamson (1863–1936) was a Scottish politician and chairman of the British Labour Party.
William Adamson may also refer to:
- William Agar Adamson (1800–1868), Canadian clergyman and author
- William Adamson (Wisconsin politician) (1834–1907), American politician
- William C. Adamson (1854–1929), U.S. Representative from Georgia
- William Adamson (Cannock MP) (1881–1945), British Labour politician
- William Adamson (Australian politician) (1858–1924), member of the Victorian Parliament
- Sir William Owen Campbell Adamson (1922–2000), British industrialist
- William Adamson, character in Angels & Insects
- William Stuart Adamson (1958–2001), Scottish guitarist, vocalist, and songwriter