John Harper is the name of:

• John Harper (politician) (died 2001), American politician from Kentucky
• John Adams Harper (1779-1816), American politician from New Hampshire
• John L. Harper (1925-2009), British biologist
• John Harper (pastor) (1872-1912), British Baptist pastor who died on the Titanic
• John Russell Harper (1914-1983), Canadian art historian
• John William Harper (1916-1944), English recipient of the Victoria Cross
• John Harper (mayor), mayor of Denver, Colorado, U.S.A, 1871-1872
• Johnny Harper, fictional character in The O.C.
• John Ernest Harper, British Vice Admiral (1874-1949)
• John Harper (computer engineer), British computer engineer who led the Bombe rebuild at Bletchley Park
• John Harper, former director of the Royal School of Church Music

[ Source: Wikipedia ]