| Gennes-sur-Seiche | |
| Native Name: | (Gallo) |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Gennes-sur-Seiches (Ille-et-Vilaine).svg |
| Coordinates: | 47.9892°N -1.1225°W |
| Insee: | 35119 |
| Postal Code: | 35370 |
| Arrondissement: | Fougères-Vitré |
| Canton: | La Guerche-de-Bretagne |
| Mayor: | Henri Beguin[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CA Vitré Communauté |
| Elevation Min M: | 58 |
| Elevation Max M: | 104 |
| Area Km2: | 18.50 |
Gennes-sur-Seiche (pronounced as /fr/; ; Gallo: Genn) is a commune in the Ille-et-Vilaine department in Brittany in northwestern France.
Inhabitants of Gennes-sur-Seiche are called Gennois in French.