AAO

AAO, AAo or aao may refer to:

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

 * Anaco Airport (IATA code AAO), Anaco, Venezuela
 * Andrushivka Astronomical Observatory, an observatory in Ukraine
 * Australian Astronomical Observatory, an observatory in Australia
 * Colonel James Jabara Airport (FAA LID: AAO), Wichita, Kansas, United States

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

 * , 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