Oder-Neisse line, frontier established in 1945 between Germany and Poland; it followed the Oder and W Neisse rivers from the Baltic Sea to the Czechoslovak border.

The boundary, desired by most Poles at the expense of Germany, came about as a result of agreements between the Soviet Union, Great Britain, and the United States at the Yalta and Potsdam conferences in 1945. The Soviet leader Joseph Stalin endorsed the Oder-Neisse line partly as a compensation for the Polish eastern territories that the USSR had annexed and partly under pressure from the USSR-sponsored Polish government.