The Potsdam Conference (German: Potsdamer Konferenz) was held in Potsdam, Germany, from July 17 to August 2, 1945 to allow the three leading Allies to plan the postwar peace, while avoiding the mistakes of the Paris Peace Conference of 1919. The participants were the Soviet Union, the United Kingdom, and the United States. They were represented respectively by General Secretary Joseph Stalin, Prime Ministers Winston Churchill and Clement Attlee, and President Harry S. Truman. They gathered to decide how to administer Germany, which had agreed to an unconditional surrender nine weeks earlier. The goals of the conference also included establishing the postwar order, solving issues on the peace treaty, and countering the effects of the war.

The foreign ministers and aides played key roles: Vyacheslav Molotov, Anthony Eden and Ernest Bevin, and James F. Byrnes. From July 17 to July 25, nine meetings were held, when the Conference was interrupted for two days, as the results of the British general election were announced. By July 28, Attlee had defeated Churchill and replaced him as Britain’s representative, with Britain's new Secretary of State for Foreign Affairs, Ernest Bevin, replacing Anthony Eden. Four days of further discussion followed. During the conference, there were meetings of the three heads of government with their foreign secretaries, as well as meetings of only the foreign secretaries. Committees that were appointed by the latter for precursory consideration of questions before the conference also met daily. During the Conference, Truman was secretly informed that the Trinity test of the first atomic bomb on July 16 had been successful. He hinted to Stalin that the U.S. was about to use a new kind of weapon against the Japanese. Though this was the first time the Soviets had been officially given information about the atomic bomb, Stalin was already aware of the bomb project, having learned about it through espionage long before Truman did.Key final decisions included: Germany would be divided into four occupation zones (among the three powers and France); Germany's eastern border was to be shifted west to the Oder–Neisse line; a Soviet-backed group was recognized as the legitimate government of Poland; and Vietnam was to be partitioned at the 16th parallel. The Soviets also reaffirmed their Yalta promise to promptly launch an invasion of Japanese-held areas.Views were also exchanged on a plethora of other questions. However, consideration of those matters was postponed into the Council of Foreign Ministers, which was now established. The conference ended with a stronger relationship between the three governments as a consequence of their collaboration, which renewed confidence that together with the other United Nations, they would ensure the creation of a just and enduring peace. Nevertheless, within 18 months relations had deteriorated and the Cold War had emerged.