The Agosta-class submarine is a class of diesel-electric attack submarine developed and constructed by the French DCNS in the 1970s to succeed the Daphné-class submarines. The submarines have served in the French Navy as well as exported to the navies of Spain and Pakistan. It also used by Royal Malaysian Navy for the training purpose. They were replaced in French service by the Rubis-class nuclear attack submarines but are still in active service with the navies of Spain and Pakistan. The French Navy grouped this model of submarine in their most capable class as an océanique, meaning "ocean-going."

An attack submarine or hunter-killer submarine is a submarine specifically designed for the purpose of attacking and sinking other submarines, surface combatants and merchant vessels. In the Soviet and Russian navies they were and are called "multi-purpose submarines". They are also used to protect friendly surface combatants and missile submarines. Some attack subs are also armed with cruise missiles, increasing the scope of their potential missions to include land targets.