| Fontenay-Mauvoisin | |
| Commune Status: | Commune |
| Arrondissement: | Mantes-la-Jolie |
| Canton: | Bonnières-sur-Seine |
| Insee: | 78245 |
| Postal Code: | 78200 |
| Mayor: | Dominique Josseaume[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CU Grand Paris Seine et Oise |
| Coordinates: | 48.965°N 1.6522°W |
| Elevation Min M: | 79 |
| Elevation Max M: | 152 |
| Area Km2: | 3.31 |
Fontenay-Mauvoisin is a commune in the Yvelines department in the Île-de-France in north-central France.