Horn may refer to:

• horn (anatomy), a hollow, pointed projection of the skin of various animals
• Horn, Austria
• horn (diacritic), a diacritic mark used to indicate that a normally rounded vowel such as o or u is to be pronounced unrounded
• horn (instrument)
  • horn, a slang term for any wind instrument
• Horn, Switzerland
• horn (telecommunications), an open-ended waveguide, of increasing cross-sectional area
• horn (telescope), a stationary radio telescope