During World War II, Lithuania experienced two brutal occupations—first by the Soviet Union and later by Nazi Germany—before being re-occupied by the Soviets.
The initial Soviet occupation began in 1940 after the secret Molotov–Ribbentrop Pact divided Eastern Europe into German and Soviet spheres of influence. As part of this agreement, the Soviets annexed Lithuania, installing a puppet government and undertaking mass Sovietization efforts. The annexation resulted in the rapid nationalization of industry, property seizures, and oppressive crackdowns on political, religious, and cultural institutions. Thousands of Lithuanians—mainly political figures, military officers, and intellectuals—were deported to Siberian gulags, with many dying in harsh conditions during the deportation campaigns.
In June 1941, Nazi Germany launched Operation Barbarossa and swiftly took control of Lithuania. Initially, many Lithuanians viewed the German forces as liberators, hoping for restored autonomy following the Soviet repression. However, German authorities quickly dissolved the Lithuanian Provisional Government formed during the June Uprising, establishing the Reichskommissariat Ostland instead. The Nazis employed Lithuanian collaborators for military operations and forced labor, leading to widespread disillusionment.
By 1944, the Soviet Red Army recaptured Lithuania, beginning the second Soviet occupation. The annexation was formalized, with Vilnius re-established as the capital of the Lithuanian Soviet Socialist Republic. Both Nazi and Soviet occupations devastated Lithuania's population and infrastructure, resulting in severe physical losses and further deportations to Siberia during the post-war Soviet regime. Despite resistance movements, including the formation of partisan units, Lithuania would remain under Soviet control until the collapse of the Soviet Union in 1990.