| Marnac | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Marnac (Dordogne).svg |
| Arrondissement: | Sarlat-la-Canéda |
| Canton: | Vallée Dordogne |
| Insee: | 24454 |
| Postal Code: | 24220 |
| Mayor: | Jean-Paul Mouillac[1] |
| Term: | 2020 - 2026 |
| Coordinates: | 44.8378°N 1.0267°W |
| Elevation M: | 120 |
| Elevation Min M: | 50 |
| Elevation Max M: | 260 |
| Area Km2: | 7.92 |
Marnac (pronounced as /fr/) is a commune in the Dordogne department in Nouvelle-Aquitaine in southwestern France.