| Marnay-sur-Marne | |
| Commune Status: | Commune |
| Arrondissement: | Chaumont |
| Canton: | Nogent |
| Insee: | 52315 |
| Postal Code: | 52800 |
| Mayor: | Stéphan Emeraux[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CA Chaumont |
| Coordinates: | 48.0111°N 5.2375°W |
| Elevation M: | 345 |
| Area Km2: | 10.62 |
Marnay-sur-Marne (pronounced as /fr/, literally Marnay on Marne) is a commune in the Haute-Marne department in north-eastern France.