Morlanwelz (French pronunciation: [mɔʁlɑ̃we]; Walloon: Marlanwé) is a municipality of Wallonia located in the province of Hainaut, Belgium. On 1 January 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 municipality consists of the following districts: , Mont-Sainte-Aldegonde, and Morlanwelz-Mariemont.