| Official Name: | Sefid Ab |
| Native Name: | سفيداب |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Mazandaran |
| Subdivision Type2: | County |
| Subdivision Name2: | Tonekabon |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Nashta |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Tameshkol |
| Population As Of: | 2006 |
| Population Total: | 170 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 36.6744°N 51.0183°W |
Sefid Ab (Persian: سفيداب, also Romanized as Sefīd Āb) is a village in Tameshkol Rural District, Nashta District, Tonekabon County, Mazandaran Province, Iran. At the 2006 census, its population was 170, in 40 families.