AK

• Alaska, a state in the United States (see United States postal abbreviations)
• applied kinesiology, a method using manual muscle testing that purportedly gives feedback on the functional status of the body
• Alicia Keys, singer.
• actinic keratosis, a skin condition
• AK, the US Navy hull classification symbol for Cargo Ship
• Armia Krajowa (Home Army), underground resistance in Nazi-occupied Poland during World War II
• AK-47 (Avtomat Kalashnikova model 1947 g.), Russian rifle or one of its variants such as the AK-74, AK-101, AK-103, or AK-107
• AK, the IATA code for AirAsia based in Malaysia
• Ace-King, a card combination in Poker
• Patient AK, a 16 year old female patient who laughed when her brain was stimulated with electric current during treatment for epilepsy
• A.K. (1985), a film directed by Chris Marker about the making of Akira Kurosawa's Ran (1985)
• AK Press, a collectively owned and operated independent publisher and book distributor that specialises in radical and anarchist literature
• AK (Radio Program), a weekly broadcast produced by Alaska Public Radio
• Knight of the Order of Australia, a chivalric award, defunct since 1986
• AK, Arbeiterkammer, in English the Austrian Chamber of Labour
• AK, the Turkish Justice and Development Party, from its Turkish name, Adalet ve Kalkınma Partisi
• In falconers' usage, "American kestrel" (a species of bird of prey)
• In database theory, Alternate key, an attributes set capable to identify a recordset not used as primary key

aK may refer to:

• attokelvin, an SI unit of temperature

ak may refer to:

• Akan language (ISO 639 alpha-2)

Ak may refer to:

• Ak, the Master Woodsman of the World in L. Frank Baum's The Life and Adventures of Santa Claus
• Ak, the nickname for bassist Steve Jay, of the ethno-funk duo, Ak & Zuie (and "Weird Al" Yankovic's bassist)