| Official Name: | San Sadurniño |
| Pushpin Map: | Spain |
| Pushpin Map Caption: | Location in Spain. |
| Subdivision Type: | Country |
| Subdivision Name: | Spain |
| Subdivision Type1: | Autonomous community |
| Subdivision Name1: | Galicia |
| Subdivision Type2: | Province |
| Subdivision Name2: | A Coruña |
| Subdivision Type3: | Comarca |
| Subdivision Name3: | Ferrol |
| Leader Title: | Mayor |
| Leader Name: | Secundino García Casal (BNG) |
| Area Total Km2: | 99.68 |
| Population Density Km2: | auto |
| Utc Offset: | +1 |
| Utc Offset Dst: | +2 |
| Coordinates: | 43.5667°N -10°W |
San Sadurniño is a municipality in the province of A Coruña in the autonomous community of Galicia in northwestern Spain. It belongs to the comarca of Ferrol. It is located in the valley of the Rio Grande de Xuvia. Sights include the ruins of the Naraío Castle and the Palaces of the marquises of San Sadurniño.