The People's Republic of Bulgaria was the official name of Bulgaria when it was a socialist republic from 1946 to 1990, ruled by the Bulgarian Communist Party (BCP) together with its coalition partner, the Bulgarian Agrarian People's Union. Bulgaria was closely allied and one of the most loyal satellite states of the Soviet Union during the Cold War, sometimes being called the 16th Soviet Republic rather than an independent country. Bulgaria was also part of Comecon as well as a member of the Warsaw Pact. The Bulgarian resistance movement during World War II deposed the Kingdom of Bulgaria administration in the Bulgarian coup d'état of 1944 which ended the country's alliance with the Axis powers and led to the People's Republic in 1946.

Bulgarian is an Eastern South Slavic language spoken in Southeast Europe, primarily in Bulgaria. It is the language of the Bulgarians.