Riola Sardo, Arriora or Arriola in sardinian language, is a comune (municipality) in the Province of Oristano in the Italian region Sardinia, located about 100km northwest of Cagliari and about 11km north of Oristano. As of 31 December 2004, it had a population of 2,132 and an area of 48.2km2. Riola Sardo borders the following municipalities: Baratili San Pietro, Cabras, Narbolia, Nurachi, San Vero Milis.
