| Castelletto d'Orba | |
| Official Name: | Comune di Castelletto d'Orba |
| Coordinates: | 44.6833°N 50°W |
| Region: | Piedmont |
| Province: | Alessandria (AL) |
| Frazioni: | Cazzuli, Crebini, Passaronda |
| Mayor: | Mario Pesce |
| Area Total Km2: | 13.98 |
| Population Footnotes: | [1] |
| Population Total: | 1958 |
| Population As Of: | 31 May 2018 |
| Population Demonym: | Castellettesi |
| Elevation M: | 200 |
| Postal Code: | 15060 |
| Area Code: | 0143 |
Castelletto d'Orba is a comune (municipality) in the Province of Alessandria in the Italian region Piedmont, located about 90km (60miles) southeast of Turin and about 25km (16miles) south of Alessandria.
Castelletto d'Orba borders the following municipalities: Capriata d'Orba, Lerma, Montaldeo, San Cristoforo, and Silvano d'Orba.