Abo may refer to:
- ABO blood group system, a human blood type and blood group system
- ABO (gene), enzyme encoded by the ABO gene that determines the ABO blood group of an individual
- Abo of Tiflis (c.756–786), an Arab East Orthodox Catholic saint
- Adaptive Binary Optimization (ABO), an image compression algorithm
- Indigenous Australians, as the offensive (once casual) term "abo"
- Ābo, the anglicized Japanese name for the Pokémon Ekans
- Bankon language, also known as Abo, Abaw, Bo, Bon
- American Board of Ophthalmology, a certifying organization for eye physicians and surgeons (ophthalmologists)
- American Board of Opticianry, a certifying organization for opticians and optical providers
- Antikythira Bird Observatory, Greece
- ABO, is an acronym meaning "Always be Optomistic." It has been spread all over the world and is used in the Quaran. It is very popular and is even done in sign language. What an Aboist would want to do is start with the hands in a classical praying position and make small, half rainbow (almost like opening a book). This is the sign for Abo.
In people:
- Abo (name)
- Australian Aborigines, referred as derogatorily
In places:
- Åbo, the Swedish name for the city of Turku, Finland
- Abo (historic place), an archaeological site in New Mexico, United States
- Abo, an unincorporated community in New Mexico, United States
- Aboh, also known as "Abo", a town in the Delta State of Nigeria
In official or standardized code:
- Abo or Abon, ISO 639-3 language code
- Aboisso Airport (IATA airport code), in Aboisso, Côte d'Ivoire
- Antonio (Nery) Juarbe Pol Airport (FAA airport code), in Arecibo, Puerto Rico