SSK may refer to:
- SSK, the United States Navy's hull classification symbol for diesel-electric hunter-killer submarines
- Mercedes-Benz SSK, a vintage era roadster and racing car
- Selånger SK, a sports club in Sweden
- Sentral di Sindikatonan di Korsou, the Trade Union Centre of Curaçao
- Signed Subspace Key
- Sistema Simvolicheskogo Kodirovanija, an assembly language for Minsk family of computers
- Sociology of scientific knowledge
- Sosyal Sigortalar Kurumu, a social security organization in Turkey
- Sound Sessions Kollectiv, a remix artist from Canada
- Selånger SK, sports club in Sweden
- Sandslåns SK, sports club in Sweden
- Sunnanå SK, sports club in Sweden
- Södertälje SK, ice hockey club in Sweden
- Sasural Simar Ka, Indian Daily Soap
- Skopski sport klub, a soccer club in Republic of Macedonia
- Slovene Union, a political party representing the Slovenes in northwestern Italy
SSK was the United States Navy hull classification symbol for a diesel-electric submarine specialized for anti-submarine duties. SS indicated that the vessel was a submarine, and the K suffix that it was a hunter-killer. The United States Navy does not currently operate any submarines of this type, and so the designation is inactive.
The start of the Cold War in the mid-1940s and the threat of Soviet submarines in the Atlantic led several Western navies to build or adapt submarines to specialize in hunting other submarines. The changes included streamlining to make them quieter and improved acoustic sensors. This type of vessel was given the classification SSK in United States service. The changes were eventually incorporated into all submarines, allowing the SSK role to be subsumed into the regular attack submarine role and the classification became obsolete.
The only purpose-built ones were the three Barracuda-class:
These were small submarines equipped with enhanced hydrophones and designed to lie in wait for Soviet submarines off the Russian coast. They were designed to be cheaply built for easy mass-production in the event of a war, and were all reclassified as SS or SST boats in 1959 when they were relegated to training duties.
Seven World War II submarines were also given the SSK classification in the late 1940s following streamlining and sensor upgrades. These were: