The is a bus service operated by the Bus Service Division, the . It is also called .
The bureau mainly operates bus routes in the special wards of Tokyo, as well as those in the city of à Âme in the western Tama Area. It creates a virtual monopoly of bus routes in the central Tokyo (the area roughly within Yamanote Line loop), while those in other parts of Tokyo Metropolis and the Greater Tokyo Area are operated by many different companies. TMBT also operates a few other bus services, such as chartered bus, school bus, and community bus. Tokyo is one of the only two Japanese prefectures that directly operate bus routes, the other being by the Transportation Bureau of Nagasaki Prefecture.
As of February 2022, there are about 200 routes with the total length of . If the sections shared by multiple routes are counted once, the length is . 1,467 bus vehicles serve 1,639 bus stops.
Toei Bus has an official mascot called , a bug-like personification of a bus vehicle.
When Tokyo Shiden (Tokyo City Streetcar, the current Tokyo Toden) lines were damaged by the Great Kantà  earthquake in 1923, Tokyo City Electricity Bureau started 2 bus routes, originally as an emergency measure. They became the origin of Tokyo City Bus. In 1942, Tokyo City bought over 8 rivaling bus companies, including of , of , and others. In 1943, TCEB changed to the Tokyo Metropolitan Bureau of Transportation, as the city changed to the metropolis.
Right after the World War II, there were only 12 routes still in operation. 400 surplus buses from U.S. force were sold to TMBT, helping its recovery. In 1948, its tourist bus division was assigned to , which now dominates tourist bus services in Tokyo. Toei Bus had a good financial condition in 1950s, but went into red from 1961. After 1963, many streetcar lines were closed, and new bus routes started their services as substitutes, making the backbone of the current network. In 1975, the bureau succeeded the routes in à Âme from Seibu Bus.
Toei Bus had the highest ridership in 1972 fiscal year, with the average of 1,298,912 daily passengers. With the growth of subway network, the ridership is continuously decreasing. It had the average of 568,863 daily passengers in 2005 fiscal year.
Toei Bus is operated with 12 bus depots and 7 branch offices. Latin letters are assigned to each depot/branch for vehicle identification and such.
Most routes are designated by one or two kanji followed by a two-digit number. Some routes have Latin alphabets instead of kanji. A number may be followed by a celestial stem (kà Â, otsu, etc., equivalent to abc or 123). The term orikaeshi is equivalent to the European bis. "Readings" provided here are tentative. There are no widely accepted English names of the routes. TMBT uses the kanji names even in English texts, like " starts from Kameari-eki Kitaguchi".
All routes are equipped with accessibility feature, such as non-step buses with kneeling function.
There are also some non-regular routes, including those for Tokyo Big Sight, the National Theatre of Japan, Kyà Âtei Course, the , and the Sumidagawa Fireworks Festival.
There are 1,467 buses used by TMBT. These are manufactured by Isuzu Motors, Hino Motors, Nissan Diesel, Mitsubishi Fusà  and Volgren (imported from Australia). The bureau is keen on introducing vehicles with accessibility feature, such as non-step buses. By the end of 2024, all buses became non-step buses. The bureau also employs relatively many eco-friendly vehicles as Japanese bus operator, including hybrid buses, 75 fuel cell and 2 electric buses.
For the routes in the special wards of Tokyo, the adult fares are as follows, regardless of the distance. Riders get on a bus from a front door, and get off from a rear door.
For the routes in à Âme, the fare varies depending on the distance. Riders get on a bus from a rear door, and get off from a front door.
All the Toei Bus cars accept , a magnetic fare collection card, as well as PASMO and Suica, contactless smart cards.