Gannon may refer to:
- Craig Gannon (born 1966), English guitarist
- Jeff Gannon (born 1957), pen name of James Guckert, a former White House reporter for the GOP-linked Talon News
- John Mark Gannon (1877–1968), former archbishop of the Diocese of Erie
- Kim Gannon (1900–1974), American songwriter
- Rich Gannon (born 1965), National Football League quarterback
- Sean Gannon (fighter), bare-knuckle fighter and mixed martial artist
- Jim Gannon (born 1968), English Football Manager
- Jim Gannon (rugby league) (born 1977), Australian professional rugby league player
- Kelli Gannon (born 1978), former field hockey midfield player from the United States
- Terry Gannon (born 1963), sportscaster for ESPN on ABC and ESPN
- Gannon University, a university in Erie, Pennsylvania
- Ian Gannon (born 1985), P6 Planner, Trouble shooter, Disc Jockey, TSG Project Manager, Professional Squash Player and German Market Ambassador.
- An early romanization of Ganon, a villain from Nintendo's video game series The Legend of Zelda