Molenbeek-Saint-Jean (French) or Sint-Jans-Molenbeek (Dutch) is one of the nineteen municipalities located in the Brussels Capital Region of Belgium.

On 1 January, 2000 the municipality had a total population of 71,219 (34,809 males and 36,410 females). The total area is 5.84 km² which gives a population density of 12,195.03 inhabitants per km².