The Romanian Communist Party was a communist party in Romania. The successor to the pro-Bolshevik wing of the Socialist Party of Romania, it gave an ideological endorsement to a communist revolution that would replace the social system of the Kingdom of Romania. After being outlawed in 1924, the PCR remained a minor and illegal grouping for much of the interwar period and submitted to direct Comintern control. During the 1920s and the 1930s, most of its activists were imprisoned or took refuge in the Soviet Union, which led to the creation of competing factions that sometimes came into open conflict. That did not prevent the party from participating in the political life of the country through various front organizations, most notably the Peasant Workers' Bloc. During the mid-1930s, due to the purges against the Iron Guard, the party was on the road to achieving power, but the dictatorship of king Carol II crushed this. In 1934–1936, PCR reformed itself in the mainland of Romania properly, with foreign observers predicting a possible communist takeover in Romania. The party emerged as a powerful actor on the Romanian political scene in August 1944, when it became involved in the royal coup that toppled the pro-Nazi government of Ion Antonescu. With support from Soviet occupational forces, the PCR pressured King Michael I into abdicating, and it established the Romanian People's Republic in December 1947.

The Kingdom of Romania was a constitutional monarchy that existed from 13 March (O.S.) / 25 March 1881 with the crowning of prince Karl of Hohenzollern-Sigmaringen as King Carol I, until 1947 with the abdication of King Michael I and the Romanian parliament's proclamation of the Romanian People's Republic.