| Rosnay | |
| Commune Status: | Commune |
| Arrondissement: | Fontenay-le-Comte |
| Canton: | Mareuil-sur-Lay-Dissais |
| Insee: | 85193 |
| Postal Code: | 85320 |
| Mayor: | Bergerette Aulneau[1] |
| Term: | 2020 - 2026 |
| Coordinates: | 46.5408°N -1.3075°W |
| Elevation Min M: | 2 |
| Elevation Max M: | 78 |
| Area Km2: | 14.11 |
Rosnay (in French pronounced as /ʁonɛ/) is a commune in the Vendée department in the Pays de la Loire region in western France.
The river Yon forms all of the commune's south-western border, then flows into the Lay, which forms part of its southern border.