Vaudreuil-Dorion is a suburb of Greater Montreal, in the Montérégie region of southwestern Quebec, Canada. The result of the merger of two towns, Vaudreuil and Dorion, it is located in the Vaudreuil-Soulanges Regional County Municipality.

Greater Montreal is the most populous metropolitan area in Quebec and the second most populous in Canada after Greater Toronto. In 2015, Statistics Canada identified Montreal's Census Metropolitan Area (CMA) as 4,258.31 square kilometres (1,644.14 sq mi) with a population of 4,027,100, almost half that of the province.