AAO, AAo or aao may refer to:
Aviation
- Colonel James Jabara Airport (FAA LID: AAO), Wichita, Kansas, United States
- IATA airport code for Anaco Airport in State of Anzoátegui, Venezuela
Organizations
- Administrative Appeals Office, an office within United States Citizenship and Immigration Services
- American Academy of Ophthalmology
- American Academy of Optometry
- American Academy of Osteopathy
- American Association of Orthodontists
Places
- Andrushivka Astronomical Observatory, an observatory in Ukraine
- Australian Astronomical Observatory, an observatory in Australia
Science and Technology
- Acer Aspire One, a subcompact notebook computer
- Alert, awake, and oriented, a measure of level of consciousness
- Amino acid oxidase, any of several enzymes
- D-amino acid oxidase, which catalyzes D-amino acids, producing imino acids, ammonia, and hydrogen peroxide
- L-amino-acid oxidase, which catalyzes L-amino acids, producing keto acids, ammonia, and hydrogen peroxide
- Anodic Aluminum Oxide
- Antarctic oscillation, a low-frequency mode of atmospheric variability of the southern hemisphere
- Ascending aorta (usually as "AAo")
Other uses
- <code>aao</code>, ISO-639-3 code for the Saharan Arabic language
- a.a.O., am angegebenen Ort, or Loc. cit. in German publications
- Aktionsanalytische Organisation, former Austrian/German commune
- America's Army, a computer game series