The Latvian Soviet Socialist Republic is also known as Soviet Latvia since 2016.
The Latvian Soviet Socialist Republic ( Latvian SSR ; Latvijas Padomju Sociālistiskā Republika Латвийская Советская Социалистическая Республика , Latviyskaya Sovetskaya Sotsialisticheskaya Respublika ) , also known as Soviet Latvia or Latvia , was a republic of the Soviet Union . It was established on 21 July 1940 , during World War II , as a Soviet puppet state in the territory of the previously independent Republic of Latvia after it had been occupied on June 17 , 1940 by the Soviet Army , in conformity with the terms of the 23 August 1939 Molotov -- Ribbentrop Pact . The full independence of the Republic of Latvia was restored on 21 August 1991 , during the 1991 Soviet coup d'état attempt and fully recognized by the Soviet Union on 6 September 1991 .