Communism in Poland can trace its origins to the late 19th century: the Marxist First Proletariat party was founded in 1882. Rosa Luxemburg (1871–1919) of the Social Democracy of the Kingdom of Poland and Lithuania (Socjaldemokracja Królestwa Polskiego i Litwy, SDKPiL) party and the publicist Stanisław Brzozowski (1878–1911) were important early Polish Marxists.
During the interwar period in the Second Polish Republic, some socialists formed the Communist Party of Poland (Komunistyczna Partia Polski, KPP). Most of the KPP's leaders and activists perished in the Soviet Union during Joseph Stalin's Great Purge in the 1930s, and the party was abolished by the Communist International (Comintern) in 1938.
In 1939, World War II began and Poland was conquered by Nazi Germany and the Soviet Union. The government of the Polish Republic went into exile. In 1942, Polish communists in German-occupied Poland established a new Polish communist party, the Polish Workers' Party (Polska Partia Robotnicza, PPR). Władysław Gomułka soon became its leader. But in the Soviet Union, Stalin and Wanda Wasilewska created the Union of Polish Patriots as a communist organization under Soviet control. As Germany was being defeated, the Polish communists cooperated with the Soviet Union, in opposition to the Polish government-in-exile, to establish a socialist Polish state with fraternal ties to the Soviet Union. This led to the creation of the Polish People's Republic. The PPR merged with the Polish Socialist Party (Polska Partia Socjalistyczna, PPS), to form the Polish United Workers' Party (Polska Zjednoczona Partia Robotnicza, PZPR), which ruled Poland until 1989. In post-World War II Poland, the communists initially enjoyed significant popular support due to the land reform, a mass scale rebuilding program, and progressive social policies. The popular support eroded because of repressions, economic difficulties, and the lack of freedoms, but the PZPR was kept in power for four decades under Soviet influence.
During this period, some Polish academics and philosophers, including Leszek Kołakowski, Tadeusz Kotarbiński, Kazimierz Ajdukiewicz, and Stanisław Ossowski, tried to develop a form of "Polish Marxism", as part of the revisionist Marxist movement. These efforts to create a bridge between Poland's history and Marxist ideology were mildly successful, especially in comparison to similar attempts elsewhere in the Eastern Bloc. But they were stifled by the regime's unwillingness to risk stepping too far in the reformist direction.
In post-1989 democratic Poland, declared communists have had a minimal impact on the political and economical life of the country. However, former communists, including members of the Politburo of the PZPR, remained active on the political scene after the transition to democracy. Some were democratically elected to top national leadership positions (e.g. Aleksander Kwaśniewski, who was a two-term president of the Polish Republic). Their center-left party, the Democratic Left Alliance (Sojusz Lewicy Demokratycznej, SLD), was one of the major political parties in Poland and was represented in the Sejm (Polish national parliament) until 2015. The influence of the so-called post-communists on the formation of the present democratic Constitution of Poland was essential.