Alexander Horn (1762–1820) was a Scottish Benedictine monk and secret agent.
Alexander Horn may also refer to: Alex Horn (1929–2007), cult leader, playwright and actor Alexander horn, a musical instrument Alexander horned sphere, a mathematical concept Alexander Horne, Governor of the Isle of Man 1713–1723 Alex Horne (born 1978), British comedian Horns of Alexander, a mythological motif associated with Alexander the Great