John Gannon

• John Gannon (Australian politician), member of the New South Wales Legislative Assembly
• John Gannon (footballer), English footballer
• John D. Gannon, American computer scientist
• John A. Gannon, American labor union leader
• Sam Gannon, real name John Gannon, Australian cricketer
• John Mark Gannon, American clergyman of the Roman Catholic Church
• John Gannon (Idaho politician), Idaho state representative
• John Gannon (Vermont politician), Vermont state Representative