Saint-Ludger is a municipality in the Le Granit Regional County Municipality in Estrie, Quebec, Canada, on the Canada–United States border.

Population is 1,074 as of 2021.

The municipality of Saint-Ludger was created in 1998 from the amalgamation of the village of Saint-Ludger, the municipality of Risborough and the township of Gayhurst-Partie-Sud-Est.

The first settlers arrived in the area before 1863.

It is named in honour of Ludger of Utrecht, the first bishop of Münster in the 9th century.