AA

• America's Army, a 2002 computer game published by the U.S. Army
• Ancient Anguish, a computer game in existence since 1992
• Aa!, a J-Pop musical group
• AA (band), South Korean boy band
• Aa (album), 2016, by Baauer
• "AA" (song), a 2021 single by Walker Hayes
• Ace Attorney, a series of video games developed by Capcom
• AA Films, an Indian film distribution company
• All American (TV series), a 2018 American sports drama series
• AA Book (disambiguation)
• "The Savages" (Doctor Who), a 1966 Doctor Who serial (production code "AA")
• Academy Award, in the film industry

Airlines

• Aerolíneas Argentinas, an Argentine airline
• AirAsia
• Air Austral airline, former logo
• American Airlines, IATA code
• Ascend Airways

Other organizations

• Alcoholics Anonymous, support organization
• A. A. Arms, a defunct firearms manufacturer
• Alcoa, a US aluminum producer, stock symbol
• Anadolu Agency, press agency, Turkey
• Arakan Army, Rakhine State, Myanmar, a rebel group
• Audio-Animatronics, used at Disney Parks
• Academia de Artes, Mexico
• Former US Amalgamated Association of Iron and Steel Workers
• Architectural Association School of Architecture, London, UK
• Astrological Association of Great Britain, London, UK
• Auswärtiges Amt, the Foreign Office of Germany
• Danish Association of Architects (Akademisk Arkitektforening)
• The AA, UK motoring organization
• AA Ireland, an Irish automotive services company
• AA Motoring Trust, merged into IAM Motoring Trust

• Albuquerque Academy, independent school in Albuquerque, New Mexico
• Appreciative advising, a method to enhance interactions between students and advisors
• Associate of Arts, an academic degree

• Aa Church, a church in Aakirkeby on the island of Bornholm
• A∴A∴, a spiritual organization created in 1907 by Aleister Crowley
• Abhisamayalankara, or Abhisamaya-alaṅkāra, a Mahayana Buddhist text
• Augustinians of the Assumption, a congregation of Catholic religious (priests and brothers)
• Statue of A'a from Rurutu, a wooden fertility-god sculpture from the Pacific island of Rurutu
• "A is A", an expression of the law of identity: each thing is identical with itself
• Iah, an ancient moon deity
• AA or A.A. (After Adam), year notation in the Mandean calendar

• aa, Latin-script digraph used in the orthographies of Dutch, Finnish, and other languages
• aa, representation of letter Å in several Scandinavian languages
• aa, a romanization of Arabic letter alif ⟨ا⟩
• Ꜳ, an orthographic ligature
• Afar language (ISO 639-1 language code aa)
• Africa Alphabet, alphabet used for African languages
• Aa (Bengali), a Bengali letter

• AA, a bra size
• AA, a width in shoe sizes
• AA battery size
• Attoampere (aA), 10⁻¹⁸ Ampere, a unit of electric current

• Aa (surname), Scandinavian surname, including a list of people with this name
• Van der Aa (surname), Dutch surname, including a list of people with this name
• Aa (architect), in Ancient Egypt
• Anthony Armstrong (writer) (1897–1972), Anglo-Canadian writer who used the pseudonym A.A. when writing for Punch
• Allu Arjun (born 1982), Indian actor, often abbreviated as AA in film titles

• Aa, Estonia, a village and beach in Estonia
• Aa, Indonesia, a populated place in the South Sulawesi province of Indonesia
• Albania, LOC MARC code
• Ann Arbor, Michigan, US
• Anne Arundel County, Maryland, US
• Antarctica, WMO country code
• Aruba, FIPS country code

Germany

• Aabach (Afte), formerly Große Aa, North Rhine-Westphalia
• Aa (Möhne), North Rhine-Westphalia
• Aa (Nethe), North Rhine-Westphalia
• Aa (Werre), North Rhine-Westphalia
• Bocholter Aa, North Rhine-Westphalia
• Dreierwalder Aa, North Rhine-Westphalia
• Kleine Aa (Aabach), a tributary of the Aabach in North Rhine-Westphalia
• Große Aa, a tributary of the Ems in Lower Saxony
• Große Aa (Aabach), a tributary of the Aabach in North Rhine-Westphalia
• Münstersche Aa, North Rhine-Westphalia
• Schaler Aa, Lower Saxony and North Rhine-Westphalia
• Speller Aa, Lower Saxony and North Rhine-Westphalia
• Steinfurter Aa, North Rhine-Westphalia

Netherlands

• Aa (Meuse), North Brabant
• Aa of Weerijs, North Brabant
• Drentsche Aa, Drenthe and Groningen
• Ruiten Aa, a river in Westerwolde, Groningen

Switzerland

• Aabach (Aare), a tributary of the Aare, in Aargau canton
• Aabach (Greifensee) or Ustermer Aa, in canton of Zürich
• Aabach (Obersee), a tributary of Obersee (Zürichsee), in canton of St. Gallen
• Aabach (Seetal), in the cantons of Lucerne and Aargau
• Chli Aa (Sempachersee), a tributary of Lake Sempach in the canton of Lucerne
• Engelberger Aa, in the cantons of Obwalden and Nidwalden
• Gross Aa (Sempachersee), a tributary of Lake Sempach in the canton of Lucerne
• Mönchaltorfer Aa, a tributary of Greifensee in canton of Zürich
• Sarner Aa (river), Obwalden, tributary of Lake Lucerne

Elsewhere

• Aa (Nete), in the province of Antwerp, Belgium; a tributary of the Nete
• Aa (France)
• Gauja, Latvia, formerly known as Livländische Aa
• Lielupe, Latvia, formerly known as Kurländische Aa

Biology

• Aa (plant), a genus of orchid
• Aa (gastropod), a subgenus of snail

Chemistry

• Arachidonic acid, a polyunsaturated fatty acid
• Azidoazide azide

Computing

• AA, Audible.com file format
• AA tree in computer science
• Adobe Animate, an animation software
• Advanced Architecture, later Amiga Advanced Graphics Architecture
• Atlas Autocode, a computer programming language
• Authoritative Answer bit, in DNS, a flag for a query answer
• ASCII Art, in internet slang
• Shift JIS art, in Japanese internet slang

Mathematics

• AA postulate of Euclidean geometry
• Abstract algebra, a branch of mathematics

Medicine

• AA amyloidosis
• Alopecia areata, a condition in which hair is lost from areas of the body
• Anesthesiologist assistant; see certified anesthesiologist assistant
• Aplastic anemia, a disease

Other uses in science and technology

• Anti-aircraft, in military use
• Attoampere (aA), 10⁻¹⁸ Ampere, a unit of electric current

Baseball

• Double-A (baseball) or Class AA, a Minor League Baseball classification level
• American Association (1882–1891), US baseball league
• American Association (1902–1997), US baseball league
• American Association of Professional Baseball, North American baseball league

Other sports

• Athletics Australia
• All-America, American amateur athletic award
• All-Australian team, all-star team of Australian rules footballers
• Amateur Athletic Union, US, since 1884

• AA Highway, Kentucky, US
• Former Ann Arbor Railroad (1895–1976), Ohio and Michigan
• Ann Arbor Railroad (1988), Ohio and Michigan
• Former K line, New York City Subway, formerly "AA"
• NZR A^A class, a New Zealand locomotive class
• Magelang, Purworejo, Kebumen, Temanggung and Wonosobo (vehicle registration prefix AA)

• ʻAʻā or aa, a form of lava
• A term for "river" in German hydronymy; see Aach (toponymy)
• Anna's Archive, a search engine for shadow libraries
• Asian Aerospace, an air show in Asia
• European Union Association Agreement
• US armed forces in the Americas (postal abbreviation AA)