Ass

Ass most commonly refers to:
 * Donkey or ass, Equus africanus asinus
 * any other member of the subgenus Asinus
 * Buttocks (in informal American English)

Ass or ASS may also refer to:

Art and entertainment

 * Ass (album), 1973 album by the band Badfinger
 * "Ass", a 2016 song by Momus from his 2016 album Scobberlotchers
 * ASS Altenburger, a German playing card manufacturer
 * Agents of Secret Stuff, a 2010 action comedy film

Science and technology

 * ASS (car), a French car made from 1919 to 1920
 * ASS (gene), a human gene that encodes for the enzyme argininosuccinate synthetase
 * Ass (M), in abstract algebra, denotes the collection of all associated primes of a module M
 * Advanced SubStation Alpha (extension .ass), a file format used for subtitles
 * Angle-side-side, condition in geometry that does not prove congruence of two triangles (also called SSA)
 * Arsenic sulfide, the basic chemical formula AsS

Other uses

 * áss, one of the Æsir in Old Norse mythology
 * Advisory Service for Squatters, a non-profit group based in London, UK
 * Alliance of Sahel States, an intergovernmental military alliance between Mali, Niger and Burkina Faso