Exo is the public transit authority serving the Greater Montreal area in Quebec, Canada. Established on June 1, 2017, Exo operates commuter trains, buses, and paratransit services across the metropolitan region, including the North and South Shores of Montreal.

The Exo network comprises five commuter rail lines, 52 stations, over 200 bus routes, and specialized transit services. It connects various municipalities to downtown Montreal, facilitating daily commutes for thousands of passengers. Exo's services are integrated within the Autorité régionale de transport métropolitain (ARTM) fare structure, allowing seamless transfers between different transit modes.

Exo's commuter trains are operated by Alstom under contract and utilize tracks owned by Canadian National Railway, Canadian Pacific Kansas City, and Exo itself. The train lines include Vaudreuil-Hudson, Saint-Jérôme, Mont-Saint-Hilaire, Candiac, and Mascouche.

In addition to fixed-route services, Exo offers on-demand transit options and paratransit services for eligible individuals. The organization is committed to providing accessible, efficient, and sustainable transportation solutions for the Greater Montreal community.