The history of Poland from 1945 to 1989 spans the period of Marxist–Leninist regime in Poland after the end of World War II. These years, while featuring general industrialization, urbanization and many improvements in the standard of living,[a1] were marred by early Stalinist repressions, social unrest, political strife and severe economic difficulties. Near the end of World War II, the advancing Soviet Red Army, along with the Polish Armed Forces in the East, pushed out the Nazi German forces from occupied Poland. In February 1945, the Yalta Conference sanctioned the formation of a provisional government of Poland from a compromise coalition, until postwar elections. Joseph Stalin, the leader of the Soviet Union, manipulated the implementation of that ruling. A practically communist-controlled Provisional Government of National Unity was formed in Warsaw by ignoring the Polish government-in-exile based in London since 1940.

The Polish People's Republic was a country in Central Europe that existed from 1947 to 1989 as the predecessor of the modern-day Republic of Poland. From 1947 to 1952 it was known as the Republic of Poland, and it was also often simply known as Poland. With a population of approximately 37.9 million near the end of its existence, it was the second most-populous communist and Eastern Bloc country in Europe. A unitary state with a Marxist–Leninist government, it was also one of the main signatories of the Warsaw Pact alliance. The largest city and official capital since 1947 was Warsaw, followed by the industrial city of Łódź and cultural city of Kraków. The country was bordered by the Baltic Sea to the north, the Soviet Union to the east, Czechoslovakia to the south, and East Germany to the west.