SLS

The initialism SLS can mean several things:

* Secured LAN segment
* MPEG-4 SLS, a scalable to lossless audio standard published by ISO
* Same language subtitle, a technique used to promote literacy through the use of subtitles
* Selective laser sintering a rapid prototyping process
* Swiss Light Source, the Swiss synchrotron
* Serviceability limit State, a factor in limit state design
* Service level specification, a technical interpretation of service level agreements
* Signaling Link Selection or Signalling Link Selection, routing label and field of the MTP2 frame in MTP
* Single-level store, memory management technology of Multics and IBM System i (AS/400)
* "Slovenska ljudska stranka", Slovenian for the Slovene People's Party
* Sodium lauryl sulfate
* Softlanding Linux System, one of the first comprehensive Linux distributions
* StarLight Scopes, image intensifier tubes used for night-vision
* Stephenson Locomotive Society
* SLS, initials of the authors of a controversial paper "Nuclear power the energy balance" by Jan Willem Storm van Leeuwen and Philip Smith
* Sim Lim Square, a popular shopping centre for computer hardware in Singapore.
* Surf lifesaving
* SmartLogic Solutions, LLC, a software & consulting firm in Baltimore, MD

In science:

* Swiss Light Source, a Swiss synchrotron at PSI, Villigen, Switzerland.

In education:

* St. Louis School, Hong Kong, a Catholic primary and secondary school
* St. Luke's School, a JK-8 independent school in New York City
* Shawnigan Lake School, a private secondary school
* Stanford University Law School
* Summer Leadership School for Air Force JROTC.

In music:
* Second Life Syndrome a 2005 album by Polish progressive metal band Riverside.
* Speech Level Singing - a singing technique