Molenbeek-Saint-Jean or Sint-Jans-Molenbeek, often simply called Molenbeek, is one of the 19 municipalities of the Brussels-Capital Region, Belgium. Located in the western part of the region, it is bordered by the City of Brussels, from which it is separated by the Brussels–Charleroi Canal, as well as by the municipalities of Anderlecht, Berchem-Sainte-Agathe, Dilbeek, Jette, and Koekelberg. The Molenbeek brook, from which it takes its name, flows through the municipality. In common with all of Brussels' municipalities, it is legally bilingual (French–Dutch).

The Brussels–Charleroi Canal, also known as the Charleroi Canal amongst other similar names, is an important canal in Belgium. The canal is quite large, with a Class IV Freycinet gauge, and its Walloon portion is 47.9 kilometres (29.8 mi) long. It runs from Charleroi (Wallonia) in the south to Brussels in the north.