The League of Communists of Serbia, known as the Communist Party of Serbia until 1952, was the ruling political party of Serbia from 1945 to 1990. It was the Serbian branch of the League of Communists of Yugoslavia, known until 1952 as the Communist Party of Yugoslavia.

The Socialist Republic of Serbia, previously known as the People's Republic of Serbia, commonly abbreviated as Republic of Serbia or simply Serbia, was one of the six constituent republics of the Socialist Federal Republic of Yugoslavia in what is now the modern day states of Serbia and the disputed territory of Kosovo. Its formation was initiated in 1941, and achieved in 1944–1946, when it was established as a federated republic within Yugoslavia. In that form, it lasted until the constitutional reforms from 1990 to 1992, when it was reconstituted, as the Republic of Serbia within the Federal Republic of Yugoslavia. It was the largest constituent republic of Yugoslavia, in terms of population and territory. Its capital, Belgrade, was also the federal capital of Yugoslavia.