Horn is a surname, and may refer to:
- Alan F. Horn
- Alfred Horn (1918–2001), American mathematician
- Horn clause is a term in formal logic named after him
- Alfred Aloysius "Trader" Horn, an African trader during the Scramble for Africa
- Anton Ludwig Ernst Horn (1774-1848), German physician
- Arvid Horn
- Blair Horn, Canadian rower
- Bob Horn
- Bruce Horn
- Cody Horn
- Corran Horn
- Dave van Horn
- Dimitris Horn (1921-1998), famous Greek actor
- Don Horn
- Frederik Winkel Horn (1845–1898), Danish writer and translator
- Frederik Winkel-Horn (1756–1837), Danish writer* Gabriel Horn
- Greg Horn
- Guildo Horn
- Gustav Horn, Count of Björneborg
- Gyula Horn, Prime Minister of Hungary from 1994–1998
- Hans Horn
- Jeremy Horn
- Jim Horn
- Joan Kelly Horn
- Joe Horn
- John S. Horn
- Joseph M. Horn
- Julian Horn-Smith
- Keith Van Horn
- Lawrence Horn
- Michael 'J' Horn a musician and musical director
- Michelle Horn
- Michiel Horn
- Mike Horn
- Milton Horn
- Noel Van Horn
- Paul Horn (b. 1930), flautist
- Dr. Paul Horn, computer scientist
- Rebecca Horn (b. 1944), German installation artist
- Sam Horn
- Shifra Horn
- Shirley Horn
- Taylor Horn
- Ted Horn
- Timothy Horn
- Tom Horn
- Tor Egil Moxness Horn
- Trevor Horn (b. 1949), British musician
- Wade F. Horn
- Welby Van Horn
- William Van Horn
Also
- Philip de Montmorency, Count of Ho(o)rn (1518-1568), a leader of the nobility in the Low Countries in the conflict escalating into the Eighty Years War
- The Horn (family) family in Finland and Sweden
- Count Arvid Horn (1664–1742), Statesman of the Swedish Empire
- Evert Horn (1585-1615), Soldier of the Swedish Empire
- Count Gustaf Horn (1592–1657), Commander of the Swedish Empire in the Thirty Years' War
