Siapiccia (Sardinian: Siapicìa) is a comune (municipality) in the Province of Oristano in the Italian region Sardinia, located about 90 kilometres (56 mi) northwest of Cagliari and about 15 kilometres (9 mi) east of Oristano. As of 31 December 2004, it had a population of 365 and an area of 17.9 square kilometres (6.9 sq mi).

Siapiccia borders the following municipalities: Allai, Fordongianus, Ollastra, Siamanna and Simaxis.

Demographic evolution