The Tokyo Metropolitan Assembly (東京都議会, Tōkyō-to gikai^?) is the prefectural parliament of Tokyo.

Its 127 members are elected every four years in 42 districts by single non-transferable vote. 23 electoral districts equal the Special wards of Tokyo, another 18 districts are made up by the cities, towns and villages in the Western part of the prefecture, one district consists of the outlying islands (Ogasawara and Izu Islands).

The assembly is responsible for enacting and amending prefectural ordinances, approving the budget (5.7 billion yen in fiscal 2007) and voting on important administrative appointments made by the governor including the vice governor.

Due to the special nature of the Tokyo metropolis compared to other prefectures the Tokyo Metropolitan Assembly has certain powers that would usually fall into the responsibilities of municipal parliaments. This is to ensure efficient and unified urban administration for the 23 special wards that cover the former city of Tokyo and comprise the urban core of the Greater Tokyo Area.

Tokyo (東京, Tōkyō^?, "Eastern Capital") [toːkʲoː], English /ˈtoʊki.oʊ/; officially Tokyo Metropolis (東京都, Tōkyō-to^?), is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of the world. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family. Tokyo is in the Kantō region on the southeastern side of the main island Honshu and includes the Izu Islands and Ogasawara Islands. Tokyo Metropolis was formed in 1943 from the merger of the former Tokyo Prefecture (東京府, Tōkyō-fu^?) and the city of Tokyo (東京市, Tōkyō-shi^?).

The Tokyo Metropolitan government administers the 23 special wards of Tokyo (each governed as a city), which cover the area that was the city of Tokyo, as well as 39 municipalities in the western part of the prefecture and the two outlying island chains. The population of the special wards is over 8 million people, with the total population of the prefecture exceeding 13 million. The prefecture is part of the world's most populous metropolitan area with upwards of 35 million people and the world's largest urban agglomeration economy with a GDP of US$1.479 trillion at purchasing power parity in 2008, ahead of New York City metropolitan area, which ranks second on the list. The city hosts 47 of the Fortune Global 500 companies, the highest amount of any city.