During the later stages of World War II and the post-war period, Germans and Volksdeutsche fled and were expelled from various Eastern and Central European countries, including Czechoslovakia and the former German provinces of Silesia, Pomerania, and East Prussia, which were annexed by Poland and the Soviet Union. The idea to expel the Germans from the annexed territories was proposed by Winston Churchill, in conjunction with the Polish and Czechoslovak exile governments in London at least since 1942. Polish prime minister Tomasz Arciszewski supported the annexation of German territory, but opposed the idea of expulsion, wanting instead to naturalize the Germans as Polish citizens and to assimilate them.

Joseph Stalin, in concert with other communist leaders, planned to expel all ethnic Germans from east of the Oder and from lands which from May 1945 fell inside the Soviet occupation zones. In 1941, his government had already transported Germans from Crimea to Central Asia.

Between 1944 and 1948, millions of people, including ethnic Germans (Volksdeutsche) and German citizens (Reichsdeutsche), were permanently or temporarily moved from Central and Eastern Europe. By 1950, a total of approximately 12 million Germans had fled or been expelled from east-central Europe into Allied-occupied Germany and Austria. The West German government put the total at 14.6 million, including a million ethnic Germans who had settled in territories conquered by Nazi Germany during World War II, ethnic German migrants to Germany after 1950, and the children born to expelled parents. The largest numbers came from former eastern territories of Germany ceded to the People's Republic of Poland and the Soviet Union (about seven million), and from Czechoslovakia (about three million).

The areas affected included the former eastern territories of Germany, which were annexed by Poland (see Recovered Territories) and the Soviet Union after the war, as well as Germans who were living within the borders of the pre-war Second Polish Republic, Czechoslovakia, Hungary, Romania, Yugoslavia, and the Baltic States. The Nazis had made plans—only partially completed before the Nazi defeat—to remove many Slavic and Jewish people from Eastern Europe and settle the area with Germans.

The death toll attributable to the flight and expulsions is disputed, with estimates ranging from 500,000–600,000 and up to 2 to 2.5 million.

The removals occurred in three overlapping phases, the first of which was the organized evacuation of ethnic Germans by the Nazi government in the face of the advancing Red Army, from mid-1944 to early 1945. The second phase was the disorganised fleeing of ethnic Germans immediately following the Wehrmacht's defeat. The third phase was a more organised expulsion following the Allied leaders' Potsdam Agreement, which redefined the Central European borders and approved expulsions of ethnic Germans from the former German territories transferred to Poland, Russia and Czechoslovakia. Many German civilians were sent to internment and labour camps where they were used as forced labour as part of German reparations to countries in eastern Europe. The major expulsions were complete in 1950. Estimates for the total number of people of German ancestry still living in Central and Eastern Europe in 1950 range from 700,000 to 2.7 million.