John Horner

John Horner may refer to:


 * John Henry Horner, also known as Cactus Jack (1927–2004), Canadian rancher, politician, and former cabinet minister
 * John M. Horner (1821–1907), founder of Union City, California
 * John S. Horner (1802–1883), American politician
 * Sir John Francis Fortescue Horner (1842–1927), British barrister
 * John Horner (British politician) (1911–1997), British firefighter, trade unionist and politician
 * John Horner (organist) (1899–1973), organist, choirmaster and music teacher in South Australia
 * John Horner (police officer), American chief of police of Los Angeles in 1885
 * John R. Horner (born 1946), American paleontologist
 * John Horner (Rector of Lincoln College, Oxford) (1792–?), Oxford college head
 * John Horner, a fictional character in The Adventure of the Blue Carbuncle, a Sherlock Holmes story by Sir Arthur Conan Doyle