Oristano is an Italian city and comune, and capital of the Province of Oristano in the central-western part of the island of Sardinia. It is located on the northern part of the Campidano plain. It was established as the provincial capital on 16 July 1974. As of December 2017, the city had 31,671 inhabitants.

The province of Oristano is a province in the autonomous island region of Sardinia, Italy. Its capital is the city of Oristano. It has an area of 3,040 square kilometres (1,170 sq mi), a total population of 160,746 (2016), and a population density of 53.7 people per square kilometer. There are 87 comuni in the province.