Société de transport de l'Outaouais (STO) is the transit service of the Outaouais region of Quebec. It operates conventional services and the Rapibus, a bus rapid transit service, in Gatineau, Quebec, including the districts of Hull, Aylmer, Gatineau, Buckingham and Masson-Angers. STO provided limited service to Chelsea and Cantley until June 2015 when Transcollines began operations in the Collines de l'Outaouais MRC. STO is located on the Quebec-side of Canada's National Capital Region, and operates several bus routes through Downtown Ottawa, Ontario.

The Rapibus is a bus rapid transit system for the Société de Transport de l'Outaouais (STO) in the city of Gatineau, Quebec. Construction was completed in the summer of 2013 with service beginning in the fall. The Rapibus aims to speed up the service for commuters in growing sub-divisions in the northern and eastern areas of the city by alleviating the congestion on key arteries currently served by bus-designated lanes. A direct link to Ottawa is included.