GO Transit is a regional public transit system serving the Greater Golden Horseshoe region of Ontario, Canada. With its hub at Union Station in Toronto, GO Transit's green-and-white trains and buses serve a population of more than seven million across an area over 11,000 square kilometres (4,200 sq mi) stretching from Kitchener in the west to Peterborough in the east, and from Barrie in the north to Niagara Falls in the south. In 2023, the system had a ridership of 56,036,900. GO Transit operates diesel-powered double-decker trains and coach buses, on routes that connect with all local and some long-distance inter-city transit services in its service area.

A bilevel car or double-decker coach is a type of rail car that has two levels of passenger accommodation as opposed to one, increasing passenger capacity.