| Official Name: | Siyah Nab |
| Native Name: | سيه ناب |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | East Azerbaijan |
| Subdivision Type2: | County |
| Subdivision Name2: | Bostanabad |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Central |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Mehranrud-e Markazi |
| Population As Of: | 2006 |
| Population Total: | 843 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 37.9289°N 46.8972°W |
Siyah Nab (fa|سيه ناب, also Romanized as Sīyah Nāb; also known as Sīnābād and Sīnāb) is a village in Mehranrud-e Markazi Rural District, in the Central District of Bostanabad County, East Azerbaijan Province, Iran. At the 2006 census, its population was 843, with 184 families.