John Simon may refer to:

• John Simon (composer) (born 1944), classical composer and poet
• John Simon (critic) (1925–2019), American author and critic
• John Simon (record producer) (born 1941), record producer for Columbia Records
• John F. Simon Jr. (born 1963), American artist and creator of Unfolding Object

• John Simon (died 1524), MP for Exeter
• John Simon (MP for Dewsbury) (1818–1897), British politician
• John Simon, 1st Viscount Simon (1873–1954), Lord Chancellor of Great Britain, 1940–1945
  • Two of his descendants who have held the title of Viscount Simon

• John Simon (rugby league) (born 1972), Australian former professional rugby league footballer
• John Simon (running back) (born 1978), American football running back
• John Simon (linebacker) (born 1990), American football linebacker
• John L. Simon, U.S. national swimming coach

• John Simon (engraver) (1675–1751), Anglo-French engraver
• Sir John Simon (pathologist) (1816–1904), Chief Medical Officer (United Kingdom), 1855–1876
• John Y. Simon (1933–2008), American Civil War scholar
• John Douglas Simon (born 1957), president of Lehigh University
• Jonathan Simon, UC Berkeley Law professor

• John Simons (born 1956), British radio executive
• John Simons (chemist) (born 1934), British physical chemist
• Jack Simons (1882–1948), Australian businessman, sports administrator and politician
• Jonathan Simons, American oncologist