| Monterosi | |
| Official Name: | Comune di Monterosi |
| Coordinates: | 42.1833°N 30°W |
| Region: | Lazio |
| Province: | Viterbo (VT) |
| Mayor: | Sandro Giglietti |
| Area Total Km2: | 10.7 |
| Population Total: | 4494 |
| Population As Of: | 31 January 2015[1] |
| Population Demonym: | Monterosini |
| Elevation M: | 276 |
| Saint: | St. Vincent and Anastasius |
| Day: | 14 September and 22 January |
| Postal Code: | 01030 |
| Area Code: | 0761 |
Monterosi is a comune (municipality) in the Province of Viterbo in the Italian region Lazio, located about 30 km (18,64 mi) north of the Grande Raccordo Anulare of Rome, about 40 km (24,85 mi) south of Viterbo.
Monterosi's territory is located halfway through between Rome and Viterbo along the Via Cassia, on the north-Easter foot of the Sabatine Hills, not far from Lake Bracciano. Within its borders lies the small Monterosi lake, legacy of a now-extinct volcanic activity in the region.
Monterosi borders the following municipalities: Nepi, Sutri, Trevignano Romano.
Monterosi was the location of one of the two known shrines of the Roman god Mutunus Tutunus.[2]