Réseau de transport de Longueuil (RTL) is a public transit system in the city of Longueuil, Quebec, Canada, and nearby communities on the South Shore of Montreal. The RTL had an annual ridership of 34,447,686 in 2013.

Longueuil is a city in the province of Quebec, Canada. It is the seat of the Montérégie administrative region and the central city of the urban agglomeration of Longueuil. It sits on the south shore of the Saint Lawrence River directly across from Montreal. The population as of the Canada 2021 Census totalled 254,483, making it Montreal's second largest suburb, the fifth most populous city in Quebec and twentieth largest in Canada.