The history of North Korea began with the end of World War II in 1945. The surrender of Japan led to the division of Korea at the 38th parallel, with the Soviet Union occupying the north, and the United States occupying the south. The Soviet Union and the United States failed to agree on a way to unify the country, and in 1948, they established two separate governments – the Soviet-aligned Democratic People's Republic of Korea and the American-aligned Republic of Korea – each claiming to be the legitimate government of all of Korea.

The division of Korea began on August 15, 1945 when the official announcement of the surrender of Japan was released, thus ending the Pacific Theater of World War II. During the war, the Allied leaders had already been considering the question of Korea's future following Japan's eventual surrender in the war. The leaders reached an understanding that Korea would be liberated from Japan but would be placed under an international trusteeship until the Koreans would be deemed ready for self-rule. In the last days of the war, the United States proposed dividing the Korean peninsula into two occupation zones with the 38th parallel as the dividing line. The Soviets accepted their proposal and agreed to divide Korea.