| Mareuil-sur-Lay-Dissais | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason Noirmoutier-en-l Ile 2.svg |
| Arrondissement: | Fontenay-le-Comte |
| Canton: | Mareuil-sur-Lay-Dissais |
| Insee: | 85135 |
| Postal Code: | 85320 |
| Mayor: | Vincent Jules[1] |
| Term: | 2020 - 2026 |
| Coordinates: | 46.5353°N -1.2275°W |
| Elevation M: | 23 |
| Elevation Min M: | 0 |
| Elevation Max M: | 78 |
| Area Km2: | 25.65 |
Mareuil-sur-Lay-Dissais (in French pronounced as /maʁœj syʁ lɛ disɛ/) is a commune in the Vendée department in the Pays de la Loire region in western France.
The river Smagne forms part of the commune's eastern border, then flows into the Lay, which flows southwestward through the commune and crosses the village.