| Le Rœulx | |
| Map: | Le Rœulx Hainaut Belgium Map.svg |
| Map-Legend: | Location of Le Rœulx in Hainaut |
| Arms: | CommunesBelgique-Le-Roeulx.svg |
| Flag: | Le Roeulx Belgium.svg |
| Arrondissement: | Soignies |
| Nis: | 55035 |
| Mayor: | Benoît Friart |
| Majority: | IC |
| Postal-Codes: | 7070 |
| Telephone-Area: | 064 |
| Web: | www.leroeulx.be |
| Coordinates: | 50.5°N 10°W |
Le Rœulx (in French pronounced as /lə ʁø/; Walloon: El Rû) is a city and municipality of Wallonia located in the province of Hainaut, Belgium.
On January 1, 2006, Le Rœulx had a total population of 7,977. The total area is 42.80 km2 which gives a population density of 186 inhabitants per km2.
The municipality consists of the following districts: Gottignies, Le Rœulx, Mignault, Thieu, and Ville-sur-Haine.
The Château du Rœulx, a family seat of the Comtes de Croÿ-Rœulx, is situated near the town.