Aglientu is a comune (municipality) in the Province of Olbia-Tempio in the Italian region Sardinia, located about 210 km north of Cagliari and about 35 km northwest of Olbia. As of 31 December 2004, it had a population of 1,126 and an area of 147.7 km².

Aglientu borders the following municipalities: Aggius, Luogosanto, Santa Teresa Gallura, Tempio Pausania, Trinità d'Agultu e Vignola. In 2005 hosted the Kitesurf World Cup. Best know in North Sardiniafor the Festa del Turista.