Siris is a comune (municipality) in the Province of Oristano in the Italian region Sardinia, located about northwest of Cagliari and about southeast of Oristano. As of 31 December 2004, it had a population of 235 and an area of .
Siris borders the following municipalities: Masullas, Morgongiori, Pompu. Alongside Ala, Ateleta, Onano and Orero, it is one of five Italian municipalities with a palindromic name.