John Hemphill may refer to:
John A. Hemphill (1927-2021), United States Army general
John Hemphill (actor) (born 1953), Canadian comic actor, writer, and producer
John Hemphill (senator) (1803–1862), American politician and judge
John J. Hemphill (1849–1912), American politician
John M. Hemphill (1892-1957), American politician