Las Plassas (Sardinian: Is Pratzas) is a comune (municipality) in the Province of Medio Campidano in the Italian region Sardinia, located about 50 kilometres (31 miles) north of Cagliari and about 15 kilometres (9 miles) northeast of Sanluri.

Las Plassas borders the following municipalities: Barumini, Pauli Arbarei, Tuili, Villamar, Villanovafranca.