The Berlin Declaration (German: Berliner Erklärung/Deklaration) of 5 June 1945 or the Declaration regarding the defeat of Germany,[n 1] had the governments of the United States, the Soviet Union, the United Kingdom, and France, acting on behalf of the Allies of World War II, jointly assume de jure "supreme authority" over Germany after its military defeat and asserted the legitimacy of their joint determination of issues regarding its administration and boundaries prior to the forthcoming Potsdam Conference.

The Allies had agreed through the European Advisory Commission a comprehensive text of unconditional surrender, which was intended to be used in the potential circumstances of Nazi power being overthrown within Germany by military or civil authorities.

In the event, Nazi power remained to the last; Adolf Hitler killed himself in the ruins of Berlin on 30 April 1945; and the claims of Karl Dönitz, his nominated successor, to have established a civil government at Flensburg were unacceptable to the Allies.

[3] The principle that hostilities against Germany should continue until its armed forces laid down their arms on the basis of unconditional surrender had been adopted by the Allies in the Moscow Declarations of October 1943, which was also stated that after a German surrender, any individuals participating in atrocities within territories under German occupation would be returned to those territories to be judged and punished, and the entire leadership of Nazi Germany, classed as "criminals," would be seized and "punished by the joint decision of the government of the Allies," a formula that was understood as indicating summary execution without trial, which remained British policy until April 1945.

That claimed authority to determine the boundaries of Germany would shortly be exercised in the incorporation of eastern territories into Poland and the Soviet Union and the short-lived creation of the Saar Protectorate in the West.

[12] The Allies maintained that the conventions could not and did not apply in the circumstances of the occupation of Germany, as the complete and lasting elimination of Nazism and its crimes against humanity and German militarism in general were their major wartime objectives.

Subsequently, the Potsdam Agreement of 1 August 1945 confirmed the establishment of British, American and French zones of occupation and set the boundary between Poland and Germany at the Oder-Neisse line.

Translated from German, it reads:On 5 June 1945 in the former headquarters of Marshal G. K. Zhukov here, the representatives of the high commands of the Anti-Hitler Coalition signed the Declaration of the defeat of Nazi Germany and the assumption of governmental authority through the four allied states.