| Native name | Ortzai |
|---|---|
| Coordinates | 40°11′N 9°9′E |
| Region | Sardinia |
| Province | Nuoro (NU) |
| Mayor | Ester Satta |
| Area total | 69.82 km² |
| Population total | 873 |
| Population as of | 31 December 2017 |
| Population demonym | Olzaesi |
| Elevation | 474 m |
| Postal code | 08020 |
| Area code | 0784 |
| Website | Official website |
Olzai (Sardinian: Ortzài) is a comune (municipality) in the Province of Nuoro in the Italian region Sardinia, located about 110 kilometres (68 mi) north of Cagliari and about 20 kilometres (12 mi) southwest of Nuoro.
Olzai borders the following municipalities: Austis, Nughedu Santa Vittoria, Ollolai, Ottana, Sarule, Sedilo, Sorradile, Teti.