| Castelliri | |
| Official Name: | Comune di Castelliri |
| Coordinates: | 41.6833°N 46°W |
| Region: | Lazio |
| Province: | Frosinone (FR) |
| Mayor: | Fabio Abballe |
| Area Total Km2: | 15.5 |
| Population Footnotes: | [1] |
| Population Total: | 3424 |
| Population As Of: | 30 June 2017 |
| Population Demonym: | Castellucciani |
| Elevation M: | 261 |
| Saint: | Santa Maria Salomè |
| Day: | October 22 |
| Postal Code: | 03030 |
| Area Code: | 0776 |
Castelliri is a comune (municipality) of c. 3,500 inhabitants in the province of Frosinone in the Italian region Lazio, located in the valley of the Liri, about 90km (60miles) southeast of Rome and about 20km (10miles) northeast of Frosinone.
Castelliri borders the following municipalities: Arpino, Isola del Liri, Monte San Giovanni Campano, Sora.