Saint-Joseph-du-Lac is a municipality in the Laurentides region of Quebec, Canada, part of the Deux-Montagnes Regional County Municipality.

The Commission scolaire de la Seigneurie-des-Mille-Îles (CSSMI) is a former francophone school district in the Canadian province of Quebec. It comprises several primary schools and high schools across municipalities in the Laurentides region. The commission is overseen by a board of elected school trustees.