Metrobus is a double decker bus model, manufactured by MCW in the 1970s and 1980s. The original MkI model was superseded by the MkII version in the early 1980s, although production of the original MkI continued for London Transport. The Metrobus was conceived as an integral product manufactured completely by MCW, but Alexander and Northern Counties also bodied some examples. The Metrobus was mainly used in the metropolitan areas of the United Kingdom, especially London and the West Midlands.

London Transport took 1,440 MkI examples between 1978 and 1985, numbering them as M1 to M1440. Two MkII prototypes were delivered to London Transport as M1441 and M1442 in 1984, but there were no further orders. In 1987 and 1988 14 secondhand Metrobuses were purchased from Greater Manchester PTE, West Yorkshire PTE and Busways . London Transport's low-cost subsidiary Harrow Buses leased 29 new MkII Metrobuses in 1987, but had to return them to their lessor three years later. London Transport's Metrobuses were the mainstay of the double decker fleet between 1987 and privatisation in 1994, when most of them passed to seven of the new operators. They remained in service for London Buses until 2004, when the last examples were withdrawn.

West Midlands Travel also took significant numbers of Metrobuses, both MkI and MkII examples. Some of these remain in service with Travel West Midlands, as the company now calls itself, at the time of writing (2004), although there are likely to be replaced by new buses over the next years.

Secondhand Metrobuses have been purchased by operators in both the United Kingdom and the Republic of Ireland. Often, these are used mainly on school contracts.