Tokyo Bay (東京湾; Tōkyō-wan) is a bay in the southern Kanto region of Japan, surrounded by the Boso Peninsula (Chiba Prefecture) and the Miura Peninsula (Kanagawa Prefecture). The ports of Tokyo, Chiba, Kawasaki, Yokohama, and Yokosuka are all located on Tokyo Bay.

On the western coast of Tokyo Bay, between Tokyo and Yokohama, the Keihin Industrial Area has been developed since the Meiji Era. This was expanded to the Keiyo Industrial Area along the north and east coasts after World War II.

The Tokyo Wan Aqua-Line bridge/tunnel crosses Tokyo Bay between Kawasaki and Kisarazu; ferries also cross the bay toward the Uraga Channel between Kurihama and Kanaya.

Tokyo Bay was the venue for Commodore Matthew Perry's early negotiations with the Japanese bakufu in the 1850's, as well as most official Japanese-European contacts preceding the Meiji Restoration.