| Agency Name: | State Security Department |
| Nativename: | Valstybės Saugumo Departamentas |
| Seal: | State Security Department of Lithuania insignia.svg |
| Formed: | 27 October 1918 (restored 26 March 1990) |
| Jurisdiction: | Government of Lithuania |
| Headquarters: | Pilaitė ave. 19, LT-06264 Vilnius, Lithuania |
| Employees: | Classified |
| Budget: | Classified |
The State Security Department or VSD (Lithuanian: Valstybės saugumo departamentas) is a Lithuanian intelligence agency which collects information on threats to the national security and works to eliminate those threats. The VSD also conducts counterintelligence, protects state secrets and classified information, and vets certain applicants for residence permits or entry to Lithuania.
The origins of the institution are in the Intelligence Unit established within the Lithuanian Armed Forces on 27 October 1918.[1] The first head of the intelligence service was Jonas Žilinskas. In 1923, many intelligence activities were transferred to the Ministry of the Interior and the institution changed its name over the time. In 1933 it was re-organized into the State Security Department with the objective to suppress espionage activities.[1] The last director of the service in the interwar period was Augustinas Povilaitis. In the aftermath of the Soviet invasion and occupation in 1940, he was arrested and executed by the Soviets.
The department was reestablished on 26 March 1990.[2] At that time, the department was also responsible for certain aspects of law enforcement: providing protection to state officials and strategic objects, ensuring integrity of state communications network, investigating political corruption. Other agencies took over these extra duties and, during 2010, the mission of VSD was clarified to mainly focus on intelligence and counterintelligence.