John Gardner may refer to:
- John Gardner (Rhode Island) (1697–1764), Deputy Governor, Colony of Rhode Island
- John Gardner (Australian politician), Australian Liberal Party MP for the South Australian seat of Morialta since 2010
- John Gardner (Continental Congress) (1747–1808), American farmer, Rhode Island delegate to Continental Congress
- John Gardner (lawyer) (born 1964), professor of jurisprudence, University of Oxford
- John Dunn Gardner (1811–1903), British Member of Parliament, 1841 to 1847
- John Fentress Gardner (1912–1998), American author and educator
- John J. Gardner (1845–1921), American politician representing New Jersey in the United States House of Representatives, 1885 to 1893
- John W. Gardner (1912–2002), U.S. Secretary of Health, Education, and Welfare during the Great Society, founder of Medicare and Public Broadcasting
- John D. Gardner (general), lieutenant general in the U.S. Army
- John L. Gardner (1793–1869), brigadier general in the US Army
- John Albert Gardner (born 1979), American double murderer
- John Sterling Gardner, Jr., American criminal, see List of individuals executed in North Carolina
- John Gardner (Texas Ranger) (1845–1926), Texas Ranger, cowboy, Indian fighter and trail boss
- John Twiname Gardner (1854–1914), English doctor and composer
- John L. Gardner (boxer), British boxer
- John Gardner (tennis), Australian tennis player, see 1971 US Open – Men's Singles