Lithuania comprises, more or less, OTL pre-1939 Lithuania, except for Memelland (Klaipėda).
In June 15, 1940, the Soviet Union invaded Lithuania and replaced the leadership. Under the occupation Latvia voluntarily joined the Soviet Union. The Soviet Union begun a series of deportations of anti-Soviet elements.
As the Third Reich attacked the Soviet Union in spring 1942, Lithuania declared her independence but this did not take long before the Germans occupied the country and incorporated as part of the Reich.
In 1952, the Third Reich granted independence of Latvia and Lithuania as Axis nations. This was merely a nominal independence, as Lithuania was a puppet state of the Reich, and the Reich military would suppress any pro-Liberal manifestation as they indeed did in 1968.
Just after the uncontested Liberal revolution in Latvia in 1981, Lithuania followed suit and Liberal leaders forced parliamentary elections with the ban of parties lifted. The governing National Socialist party only got 26% of the votes, still a plurality but surpassed by a coalition of Liberal and Conservative parties which introduced a series of reforms, granting further democracy.