SL may refer to:

Arts and entertainment

* SL (rapper), a rapper from London * ''Second Life'', a multi-user 3D virtual world * Sensei's Library, an Internet site dedicated to the game of Go * Subdominant leittonwechselklänge * Leica SL, a mirrorless system camera by Leica Camera AG

Business and organizations

* Sociedad Limitada, the Spanish version of a private limited company

Politics

* Serbian Left (2022), Serbian Left (''Srpska levica''), a political party in Serbia * Stronnictwo Ludowe, a defunct Polish political party * Soyons Libres, a French political party

Transportation and vehicles

* SL Corporation, a Korean auto parts company * Rio Sul Serviços Aéreos Regionais (IATA code SL), a Brazilian airline * Salt Lake City Southern Railroad (reporting mark SL) * Stor-Oslo Lokaltrafikk, a public transport operator in Akershus, Norway * Storstockholms Lokaltrafik, the public transport operator in Stockholm, Sweden * Thai Lion Air (IATA airline code SL) * Mercedes-Benz SL-Class, an automobile

Trade unions

* Association of Social Educators, a trade union in Denmark

Geography

* Sierra Leone, in West Africa, ISO 3166 code * Saarland, a state of Germany * SL postcode area of the United Kingdom * Sungai Long, in Selangor, Malaysia

Language

* Sl (digraph), a Latin-script digraph * Sign language, used by deaf persons * Slovene language (ISO 639-1 code "sl")

Science, technology, and mathematics

Biology

* ''Sensu#Examples in practical taxonomy, Sensu lato'', a term used in taxonomy to mean "in the wider sense" of a definition * Standard length, a common measurement for fish * Abbreviation for × Sophrolaelia, × ''Sophrolaelia'', an orchid genus

Computing

* sl, a humorous command in some Unix-based systems that draws an animation of a steam locomotive, intended to be invoked as a typo of ls * .sl, the country code top-level domain for Sierra Leone * SL (complexity), a class of computational complexity * Scientific Linux, a Linux distribution * Wireless Application Protocol, Service Loading, a variant of WAP push method

Mathematics

* SL (complexity), a class of computational complexity * sl (elliptic function), sine lemniscate function * Special linear group in mathematics, denoted SL_n * Special linear Lie algebra, denoted

\mathfrak_n(F)

\mathfrak(n, F)

Other uses

* Serjeant-at-law, a former type of barrister in England and Ireland * ''Sine loco'' in bibliographies means that place of publication is unknown