| Saint-Rieul | |
| Native Name: | Sant-Rieg |
| Commune Status: | Commune |
| Coordinates: | 48.4431°N -2.4183°W |
| Insee: | 22326 |
| Postal Code: | 22270 |
| Arrondissement: | Saint-Brieuc |
| Canton: | Lamballe-Armor |
| Mayor: | Catherine Drezet[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CA Lamballe Terre et Mer |
| Elevation Min M: | 64 |
| Elevation Max M: | 106 |
| Area Km2: | 6.37 |
Saint-Rieul (in French pronounced as /sɛ̃ ʁjœl/;) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.
Inhabitants of Saint-Rieul are called rieulais in French.