SWS
SWS, SWs, or sWS my refer to:

Education
Sacramento Waldorf School, Pre-K-12 coeducational private school in Sacramento, California
School within a School, a democratic education program at Brookline High School

Machines
M21 Sniper Weapon System, a US Army sniper rifle
M24 Sniper Weapon System, a US Army sniper rifle
Schwere Wehrmachtschlepper German half-track vehicle deployed late into World War II
SWS (trolleybus), a hybrid trolleybus prototype

Technology
Scientific Workflow System, scientific application software that composes, executes, and manages workflows
Seawater scale, a measure of concentration of H+, HSO4+, and HF
Semantic Web service, a Web service that can be published, discovered, composed, and executed by Web applications
Sentient World Simulation, a project to be based on Synthetic Environment for Analysis and Simulations
Silly window syndrome, a TCP flow control problem in computer networks
Sine wave speech, a speech synthesis technique that replaces formants with pure tone whistles
Smart wearable system, an extension of the wearable computer

Other uses
Safe Water System, initiative by the US Centers for Disease Control and Prevention to improve water quality
Schweizerische Wagons- und Aufzügefabrik AG Schlieren-Zürich, a now defunct Swiss railway rolling stock manufacturer
Seann William Scott (b. 1976), US actor
Shaun White Snowboarding, a 2008 video game
Sleeping With Sirens, an American post-hardcore band
Slow-wave sleep, deep sleep
Social Weather Stations, a social research institution in the Philippines
Society of Wetland Scientists, a US non-profit organization
Southern Water Services, a private utility company responsible for public wastewater collection and treatment in South England
SouthWest Service, a Metra route to Manhattan, Illinois
Sozialwerke Pfarrer Sieber, a Swiss charity and relief organization founded by Pastor Ernst Sieber
Super World of Sports, a Japanese professional wrestling promotion
SWS, IATA airport code for Swansea Airport
SWs, listener missives that express appreciation for Sarah Kennedy's breakfast show on BBC Radio 2