The Empire of Japan (Kyūjitai: 大日本帝國; Shinjitai: 大日本帝国; pronounced Dai Nippon Teikoku; officially Empire of Greater Japan or Greater Japanese Empire; more widely known as Imperial Japan or the Japanese Empire) was a Japanese political entity that existed during the period from the Meiji Restoration in 1868 until its defeat in World War II in 1945.

The country's rapid industrialization and militarization under the slogan Fukoku Kyohei富国強兵 (Enrich the Country, Strengthen the Military), led to its emergence as a world power eventually culminating with its membership in the Axis alliance and the conquest of a large part of the Asia-Pacific region.

The Empire of Japan, after suffering numerous defeats during the Pacific War and the atomic bombings of Hiroshima and Nagasaki, surrendered to the Allies on September 2, 1945. A period of occupation by the Allies followed the surrender and dissolution of the Empire and a new constitution was created with American involvement. American occupation and reconstruction of the country continued well into the 1950s eventually forming the current modern Japan.

The Emperors during this time, which spanned the Meiji, Taishō and Shōwa eras, are now known by their posthumous names which coincide with those era names: Emperor Meiji (Mutsuhito), Emperor Taishō (Yoshihito) and Emperor Shōwa (Hirohito).