| Saint-Just | |
| Native Name: | (Gallo) |
| Commune Status: | Commune |
| Coordinates: | 47.7664°N -1.96°W |
| Insee: | 35285 |
| Postal Code: | 35550 |
| Arrondissement: | Redon |
| Canton: | Redon |
| Mayor: | Daniel Mahé[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Redon Agglomération |
| Elevation Min M: | 8 |
| Elevation Max M: | 94 |
| Area Km2: | 28.05 |
Saint-Just (pronounced as /fr/; br|Sant-Yust; Gallo: Saent-Just) is a commune in the Ille-et-Vilaine department of Brittany in northwestern France.