AAO, AAo or aao may refer to:
Organizations Administrative Appeals Office, an office within US 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 Colonel James Jabara Airport (FAA LID: AAO), Wichita, Kansas, US Anaco Airport in Anzoátegui, Venezuela (IATA airport code AAO)
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 "AAO" (song), a 2015 single by Kis-My-Ft2 Saharan Arabic language (ISO-639-3 code "aao") 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