Do may refer to:
- The first note of the Musical scale in solfege.
- Dominique van Hulst, stage name Do, an Eindhoven Netherlands-born singer
- Marshall Applewhite, nicknamed Do, the leader of the Heaven's Gate cult
- A fictional martial art practiced by the Akashic Brotherhood in the role-playing game Mage: The Ascension
- Dominicana de AviaciÃ³n (IATA code: DO), the national and international airline of the Dominican Republic from 1944-1995
- Dornier Flugzeugwerke (Do) aircrafts
- A prosign for Morse Code
- The part of the armor that protects the trunk (cuirass) in Japanese martial arts
Do can be an abbreviation for:
- DenominaciÃ³n de Origen, a Spanish appellation
- ditto, meaning "repeat the above info here"
- Diffractive Optics, a lens design used on Canon EF lenses to reduce chromatic aberrations and weight
- Directorate of Operations, previously the American national authority for coordinating U.S. human intelligence (HUMINT) services
- Director of Operations<...