| Bréal-sous-Montfort | |
| Native Name: | (Gallo) |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Bréal-sous-Montfort (Ille-et-Vilaine).svg |
| Coordinates: | 48.0486°N -1.8653°W |
| Insee: | 35037 |
| Postal Code: | 35310 |
| Arrondissement: | Rennes |
| Canton: | Le Rheu |
| Mayor: | Bernard Éthoré[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CC de Brocéliande |
| Elevation Min M: | 19 |
| Elevation Max M: | 82 |
| Area Km2: | 33.82 |
Bréal-sous-Montfort (pronounced as /fr/, literally Bréal under Montfort; Gallo: Beréau,) is a commune in the Ille-et-Vilaine department in the region in Brittany in northwestern France.
It is located in the outer southwest district of Rennes, near the Broceliand woods.
The Meu forms the commune's northeastern border.
Inhabitants of Bréal-sous-Montfort are called Bréalais in French.