Ozieri (Sardinian: Otieri) is a comune (municipality) of approximatively 11,000 inhabitants in the Metropolitan City of Sassari, in the Italian region of Sardinia, in the Logudoro historical region.
Its cathedral of the Immacolata is the episcopal see of the Roman Catholic Diocese of Ozieri. Ozieri is the centre of the earliest known archaeological culture on Sardinia (known as Ozieri culture).
The Ozieri culture (or San Michele culture) was a prehistoric pre-Nuragic culture that occupied Sardinia from c. 3200 to 2800 BCE. The Ozieri was the culmination of the island's Neolithic culture and takes its name from the locality where early findings connected with it have been found, the cave of San Michele near Ozieri, in northern Sardinia. The Ozieri existed contemporaneously with the Arzachena culture, sharing some similarities, and its influence also extended to nearby Corsica.