| Messac | |
| Commune Status: | Commune |
| Arrondissement: | Jonzac |
| Canton: | Les Trois Monts |
| Insee: | 17231 |
| Postal Code: | 17130 |
| Mayor: | Bernard Seguin[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Haute-Saintonge |
| Coordinates: | 45.3472°N -0.3125°W |
| Elevation M: | 65 |
| Elevation Min M: | 45 |
| Elevation Max M: | 106 |
| Area Km2: | 7.24 |
Messac (in French pronounced as /mesak/) is a commune in the Charente-Maritime department in southwestern France.