Victory over Japan Day (also known as V-J Day, Victory in the Pacific Day, or V-P Day) is the day on which Imperial Japan surrendered in World War II, in effect bringing the war to an end. The term has been applied to both of the days on which the initial announcement of Japan's surrender was made – 15 August 1945, in Japan, and because of time zone differences, 14 August 1945 (when it was announced in the United States and the rest of the Americas and Eastern Pacific Islands) – as well as to 2 September 1945, when the surrender document was signed, officially ending World War II.

15 August is the official V-J Day for the United Kingdom, while the official US commemoration is 2 September. The name, V-J Day, had been selected by the Allies after they named V-E Day for the victory in Europe.

On 2 September 1945, formal surrender occurred aboard the battleship USS Missouri in Tokyo Bay. In Japan, 15 August usually is known as the "memorial day for the end of the war" (終戦記念日, Shūsen-kinenbi); the official name for the day, however, is "the day for mourning of war dead and praying for peace" (戦没者を追悼し平和を祈念する日, Senbotsusha o tsuitōshi heiwa o kinensuru hi). This official name was adopted in 1982 by an ordinance issued by the Japanese government.