| Onci | |
| Coordinates: | 43.3942°N 11.1214°W |
| Province: | Siena (SI) |
| Comune: | Colle di Val d'Elsa |
| Elevation M: | 204 |
| Population Total: | 36 |
| Population As Of: | 2011 |
Onci is a village in Tuscany, central Italy, located in the comune of Colle di Val d'Elsa, province of Siena. At the time of the 2001 census its population was 25.[1]