John Farmer may refer to:
John Farmer (composer) (c. 1570–c. 1601), Renaissance composer of madrigals
John Farmer (author) (1789–1838), American historian and genealogist
John Farmer (cartographer) (1798–1859), Detroit-based mapmaker
John Farmer (1835–1901) (1835–1901), music teacher at Harrow School
John Stephen Farmer (1854–1916), lexicographer and spiritualist
John Bretland Farmer (1865–1944), botanist
John Hind Farmer (1917–2012), SOE Agent, MI6 Agent
John Farmer (footballer) (born 1947), English footballer who played for Stoke City
John Farmer Jr. (born 1957), Attorney General, acting governor of New Jersey, and law school dean
John Q. Farmer (1823–1904), Minnesota politician and jurist
