TSS may stand for:
In science and technology:
- Time Sharing System/360, an early attempt at time-sharing by IBM
- Task State Segment, a special structure on x86-based computers which holds information about a task
- Total suspended solids, a water quality measurement
- Toxic shock syndrome, a potentially fatal illness caused by a bacterial toxin
- Transcription start site, the starting point of the process of creating a complementary RNA copy of a sequence of DNA
- Tromsø Satellite Station
In sport:
- Tideway Scullers School, a rowing club in London, England
In organizations:
- Technical Services Staff, a component of the U.S. Central Intelligence Agency
- Times Square Stores, a Long Island, New York-based retail department store chain
- Tinana State School, a public primary school in Maryborough, Queensland, Australia
- The Southport School, an Anglican day and boarding school located on Gold Coast, Queensland, Australia
- Thornhill Secondary School, a school in Thornhill, Ontario, Canada
- TSS, the New York Stock Exchange symbol for Total System Services, Inc.
In media:
- Ton Steine Scherben, a German rock band
- TV Shinhiroshima, a TV station serving in Hiroshima Prefecture and eastern Yamaguchi Prefecture
- The Sims Social, a social networking game on Facebook, based on The Sims Series
In other:
- Total sum of squares, a quantity that appears as part of a standard way of presenting results
- Traffic Separation Scheme, a traffic-management route-system ruled by the International Maritime Organization
- Twin screw steamer, a steam-powered vessel
- Therapeutic staff support - Individuals who work individually with children with behavioral disabilities in the location perscribed by the psychologist. The psychologist and behavior specialist consultant create a treatment plan and create goals for the client to reach over time. The TSS implements methods and interventions from the treatment plan to help the client achieve his or her behavior goals.