| Official Name: | Gandak |
| Native Name: | گندك |
| Settlement Type: | village |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Tehran |
| Subdivision Type2: | County |
| Subdivision Name2: | Damavand |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Rudehen |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Mehrabad |
| Population As Of: | 2006 |
| Population Total: | 30 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
Gandak (Persian: گندك, also Romanized as Gandaḵ) is a village in Mehrabad Rural District, Rudehen District, Damavand County, Tehran Province, Iran. At the 2006 census, its population was 30, in 11 families.