The military occupation of Lithuania by Nazi Germany lasted from the German invasion of the Soviet Union on June 22, 1941, to the end of the Battle of Memel on January 28, 1945. At first the Germans were widely welcomed as liberators from the repressive Soviet regime which occupied Lithuania prior to the German arrival. In hopes of re-establishing independence or regaining some autonomy, Lithuanians organized a Provisional Government. Thousands of Lithuanian nationalists then cooperated with the Generalkommissariat, jointly killing almost 200,000 Jews, which marks the highest death rate proportionally in any country during the Holocaust.
Background
In August 1939, the Soviet Union and Nazi Germany signed the German–Soviet Nonaggression Pact and its Secret Additional Protocol, dividing Central and Eastern Europe into spheres of influence. Lithuania was initially assigned to the German sphere, likely due to its economic dependence on German trade. After the March 1939 ultimatum regarding the Klaipėda Region, Germany accounted for 75% of Lithuanian exports and 86% of its imports. To solidify its influence, Germany suggested a German–Lithuanian military alliance against Poland and promised to return the Vilnius Region, but Lithuania held to its policy of strict neutrality. When Germany invaded Poland in September 1939, the Wehrmacht took control of the Lublin Voivodeship and eastern Warsaw Voivodeship, which were in the Soviet sphere of influence. To compensate the Soviet Union for this loss, a secret codicil to the German–Soviet Boundary and Friendship Treaty transferred Lithuania to the Soviet sphere of influence, which would serve as the justification that enabled the Soviet Union to occupy Lithuania on June 15, 1940, and to establish the Lithuanian SSR.
Almost immediately after the German–Soviet Boundary and Friendship Treaty, the Soviets pressured the Lithuanians into signing the Soviet–Lithuanian Mutual Assistance Treaty. According to this treaty, Lithuania gained about of territory in the Vilnius Region (including Vilnius, Lithuania's historical capital) in return for five Soviet military bases in Lithuania (total 20,000 troops). The territories that Lithuania received from the Soviet Union were the former territories of the Second Polish Republic, disputed between Poland and Lithuania since the times of the Polish-Lithuanian War of 1920 and occupied by the Soviet Union following the Soviet invasion of Poland in September 1939. The Soviet–Lithuanian Treaty was described by The New York Times as "virtual sacrifice of independence." Similar pacts were proposed to Latvia, Estonia, and Finland. Finland was the only state to refuse such a treaty and that sparked the Winter War. This war delayed the occupation of Lithuania: the Soviets did not interfere with Lithuania's domestic affairs and Russian soldiers were well-behaved in their bases. As Winter War ended in March and Germany was making rapid advances in the Battle of France, the Soviets heightened anti-Lithuanian rhetoric and accused Lithuanians of kidnapping Soviet soldiers from their bases. Despite Lithuanian attempts to negotiate and resolve the issues, Soviet Union issued an ultimatum on June 14, 1940. Lithuanians accepted the ultimatum and Soviet military took control of major cities by June 15. The following day identical ultimatums were issued to Latvia and Estonia. To legitimize the occupation, the Soviets staged elections to the so-called People's Seimas, which then proclaimed establishment of the Lithuanian Soviet Socialist Republic. This allowed Soviet propaganda to claim that Lithuania voluntarily joined the Soviet Union.