Metrolinx is a transportation agency in Ontario, Canada. It is a Crown agency that manages and integrates road and public transportation in the Greater Toronto and Hamilton Area (GTHA). It was created as the Greater Toronto Transportation Authority on June 22, 2006, and adopted its present name as a brand name in 2007 and eventually as the legal name in 2009. It is headquartered at Union Station in Toronto.
Metrolinx serves as the central procurement agency on behalf of Ontario municipalities for local transit vehicles, equipment and services. It is also responsible for operating the GO Transit system, the Presto card used across the GTHA and by OC Transpo in Ottawa and the Union Pearson Express airport rail link to Toronto Pearson International Airport.