GO Transit is a regional public transit service operating in Ontario, Canada, primarily serving the Greater Toronto and Hamilton Area (GTHA) and extending to surrounding regions. Managed by Metrolinx, an agency of the Government of Ontario, GO Transit provides both commuter rail and intercity bus services, facilitating efficient and reliable transportation across a vast network.

Established in 1967, GO Transit has grown to encompass seven train lines and numerous bus routes, connecting key urban centers such as Toronto, Hamilton, Mississauga, Brampton, and extending to areas like Kitchener, Barrie, and Niagara Falls. The central hub of GO Transit is Union Station in downtown Toronto, from which most train lines radiate.

The train services operate on diesel-powered, double-decker trains, designed to accommodate a high volume of passengers while ensuring comfort and safety. The bus fleet complements the rail network by providing connections to areas not directly served by train, offering flexibility and extended reach.

GO Transit has implemented the PRESTO card system, a reloadable smart card that allows for seamless fare payment across various transit systems in Ontario, including TTC, MiWay, and YRT. This integration simplifies the commuting experience for passengers who utilize multiple transit services.

In recent years, GO Transit has embarked on the GO Expansion project, aiming to enhance service frequency, introduce electrification on key corridors, and improve overall system capacity. This initiative reflects a commitment to sustainable and efficient public transportation solutions for the growing population of the region.