John Gannon

John Gannon may refer to:
 * John Gannon (Australian politician) (1830–1887), member of the New South Wales Legislative Assembly
 * John Gannon (footballer) (born 1966), English footballer
 * John D. Gannon (1948–1999), American computer scientist
 * John A. Gannon (1923–1997), American labor union leader
 * Sam Gannon (born 1947), real name John Gannon, Australian cricketer
 * John Mark Gannon (1877–1968), American clergyman of the Roman Catholic Church
 * John Gannon (American politician), Idaho State Representative
 * John Gannon (Vermont politician), Vermont State Representative