Military Intelligence and Security Service (, MUST) is a division of the Swedish Armed Forces Central Command. MUST is both a foreign intelligence and a military security/counterintelligence agency. In its intelligence role, MUST is responsible for providing intelligence on foreign threats to the Government of Sweden and the Swedish Armed Forces. However, signals intelligence is handled by a separate civilian agency operated by the Ministry of Defence, the Swedish National Defence Radio Establishment (FRA), which is not part of MUST. MUST is legally prohibited from gathering intelligence on Swedish domestic affairs, except in its more narrowly defined role a counter-intelligence agency tasked with identifying threats to the armed forces, such as sabotage, espionage, or infiltration. Domestic security and civilian counterintelligence in non-military contexts are handled by the Swedish Security Service (SÄPO), the civilian equivalent agency to MUST.

Departments

MUST consists of the following departments: MUST co-operates on various matters with other defence agencies, including the Swedish National Defence Radio Establishment (FRA), the Swedish Defence Research Agency (FOI), and the Swedish Defence Materiel Administration (FMV). The current Director of MUST is Major General Thomas Nilsson. Even though MUST is technically a part of the military, a majority of its staff is civilian.

Directors