Operation Osen ("Fall"; Russian: Операция «Осень», Lithuanian: Operacija „Ruduo“) was a mass deportation carried out by the Ministry of State Security (MGB) in the territory of the Lithuanian SSR in the autumn of 1951. During the operation, more than 5,000 families (over 20,000 people) were transported to remote regions of the Soviet Union. It was the last large deportation in the series of Soviet deportations from Lithuania. The operation was a dekulakization campaign specifically targeting peasants who resisted collectivisation and refused to join the kolkhozes (collective farms).
After two large deportations in May 1948 (code name Vesna) and in March 1949 (code name Priboi), the progress of collectivisation in the Lithuanian SSR jumped from 3.9% in January 1949 to 60.5% in January 1950. However, the pace of collectivization in Lithuania was still not as rapid as in Latvia or Estonia, where 93% and 80% of the farms were collectivized by the end of 1949. Soviet authorities, striving to complete the forced collectivisation in Lithuania, initiated preparations for a mass deportation of peasants who refused to join newly established kolkhozes. On September 5, 1951, the Council of Ministers of the Soviet Union issued a decree number 3309-1568cc "On the deportation of kulaks and their families from the Lithuanian territory". The decree was signed by Joseph Stalin, Premier of the Soviet Union, and Mikhail Pomaznev , Administrator of Affairs of the Council of Ministers, and ordered "to eternally transfer 4000 anti-kolkhoz kulaks and their families to Krasnoyarsk Krai and Tomsk Oblast".