Tokyo (Wikipedia) Tokyo (/ˈtoʊkioʊ/; Japanese: 東京, Tōkyō, [toːkʲoː]), officially the Tokyo Metropolis (東京都, Tōkyō-to), is the capital of Japan and the most populous city in the world with a population of over 14 million residents as of 2023. The Tokyo metropolitan area, which includes Tokyo and nearby prefectures, is the world’s most-populous metropolitan area with 40.8 million residents as of 2023.