| Official Name: | Fenesk |
| Native Name: | فنسك |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Semnan |
| Subdivision Type2: | County |
| Subdivision Name2: | Mehdishahr |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Shahmirzad |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Poshtkuh |
| Population As Of: | 2006 |
| Population Total: | 25 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 36.0514°N 53.46°W |
Fenesk (Persian: فنسك; also known as Fīnesk and Qenīsk) is a village in Poshtkuh Rural District, Shahmirzad District, Mehdishahr County, Semnan Province, Iran. At the 2006 census, its population was 25, in 7 families.