SS or ss or Ss may be:

• The Schutzstaffel, a Nazi paramilitary force
• In British heraldry, a "collar of SS" is an ornamental collar of many chained letters S; the "S" is said to stand for "[I serve my] sovereign".
• Sassari province of Italy
• Steamship (SS) (ship prefix)
• Secret Service
• A submarine not powered by nuclear energy (SS) (United States Navy designator), see SSN
• Shortstop, abbreviated SS, is an infield defensive position in baseball.
• Social security
• Special Service soldiers in British service during World War II, later renamed Commandos.
• Swallow Sidecar, now Jaguar
• Super Sport (SS) is the abbreviation for the performance package that the Chevrolet automobile division of General Motors uses on certain models. It can include high-perfomance engine, suspension, tire and alternate body styling options. It was first used on the Impala model in 1961.
• Stockholm Skins, a neo-nazi organization in Stockholm, Sweden.
• SS is the former Dutch "State Railway Exploitation Company", see also Railway stations in the Netherlands#D.
• Abbreviation for Saints in e.g. "SS Peter and Paul"
• Stockholms spårvägar, now a part of Storstockholms lokaltrafik.
• Social Studies
• the IATA code for Corsair

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