Military Intelligence and Security Service (Swedish: Militära underrättelse- och säkerhetstjänsten, MUST) is a division of the Swedish Armed Forces Central Command.

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.

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.