John Platt may also refer to:
- John Platt (Principal Researcher)
- John Platt (MP) (1817-1872), English manufacturer of textile machinery and Liberal politician.
- John Platt (footballer), footballer who played as a goalkeeper in the Football League for Tranmere Rovers
- John Platts-Mills (1906–2001), British Labour Party politician
- John Milton Platt (1840–1919), physician and political figure in Ontario, Canada.
- John R. Platt (1918-1992), American physicist and biophysicist