Ulassai (Ulassa in Sardinian language) is a comune (municipality) in the Province of Nuoro in the Italian region Sardinia, located about 70 kilometres (43 mi) northeast of Cagliari and about 20 kilometres (12 mi) southwest of Tortolì.

Ulassai borders the following municipalities: Esterzili, Gairo, Jerzu, Osini, Perdasdefogu, Seui, Tertenia, Ussassai, Villaputzu.

Historical population

Year Pop. ±% 1861 1,575 —     1871 1,591 +1.0% 1881 1,650 +3.7% 1901 2,079 +26.0% 1911 2,193 +5.5% 1921 2,220 +1.2% 1931 2,247 +1.2% 1936 2,224 −1.0%	Year Pop. ±% 1951 2,320 +4.3% 1961 2,435 +5.0% 1971 2,193 −9.9% 1981 2,050 −6.5% 1991 1,732 −15.5% 2001 1,613 −6.9% 2011 1,517 −6.0% 2021 1,369 −9.8%
Source: ISTAT