| 21 Jul 1940 |
Lithuania is declared a Soviet Socialist Republic in accordance with a declaration passed by the Liaudies Seimas 21 Jul 1940 (Vyriausybės Žinios, No. 719, 22 Jul 1940, pp. 719-720) |
| 21 Jul 1940 - 11 Mar 1990 |
Lietuvos Tarybų Socialistinė Respublika = (to 18 Nov 1988) Litovskaja Sovetskaja Socialističeskaja Respublika (Литовская Советская Социалистическая Республика) | Lithuanian Soviet Socialist Republic |
| 21 Jul 1940 |
Lithuania applies for accession to the Union of Soviet Socialist Republics in accordance with a declaration passed by the Liaudies Seimas 21 Jul 1940 (Vyriausybės Žinios, No. 719, 22 Jul 1940, pp. 720-721) |
| 3 Aug 1940 |
admitted to the Union of Soviet Socialist Republics in accordance with a law passed by the Supreme Council of the Union of the Soviet Socialist Republics 3 Aug 1940 (USSR Supreme Soviet, 1st Soviet, 7th session, 1940, 91-92, 186) |
| 18 Nov 1988 |
Lithuanian is declared state language in accordance with a law passed by the Aukščiausioji Taryba 18 Nov 1988 |
| 18 May 1989 |
declaration of state sovereignty |
