Morlanwelz is a Walloon municipality located in the Belgian province of Hainaut. On January 1, 2006 Morlanwelz had a total population of 18,595. The total area is 20.26 km² which gives a population density of 918 inhabitants per km². Its postcode is 7140.
The Morlanwelz municipality includes the old communes of Morlanwelz-Mariemont, Carnières and Mont-Sainte-Aldegonde.