| Official Name: | Bidak |
| Native Name: | بيدك |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Razavi Khorasan |
| Subdivision Type2: | County |
| Subdivision Name2: | Sabzevar |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Rud Ab |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Kuh Hamayi |
| Population As Of: | 2006 |
| Population Total: | 31 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 35.5958°N 57.1539°W |
Bidak (Persian: بيدك, also Romanized as Bīdak; also known as Kalāteh-ye Bīdak) is a village in Kuh Hamayi Rural District, Rud Ab District, Sabzevar County, Razavi Khorasan Province, Iran. At the 2006 census, its population was 31, in 8 families.