| Saint-Mars-sur-Colmont | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason Saint-Mars-sur-Colmont.svg |
| Arrondissement: | Mayenne |
| Canton: | Gorron |
| Insee: | 53237 |
| Postal Code: | 53300 |
| Mayor: | Odile Aveneau[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Bocage Mayennais |
| Coordinates: | 48.3758°N -0.6964°W |
| Elevation M: | 170 |
| Elevation Min M: | 108 |
| Elevation Max M: | 202 |
| Area Km2: | 16.39 |
Saint-Mars-sur-Colmont (pronounced as /fr/, literally Saint-Mars on Colmont) is a commune in the Mayenne department in north-western France.[2] The river Colmont, a tributary of the Mayenne, flows through the commune.