Cossoine is a comune (municipality) in the Province of Sassari in the Italian region Sardinia, located about 140 km north of Cagliari and about 35 km southeast of Sassari. Cossoine borders the following municipalities: Bonorva, Cheremule, Giave, Mara, Padria, Pozzomaggiore, Romana, Semestene, Thiesi. Sights include the churches of Santa Maria Iscalas, an example of Byzantine architecture (6th-11th centuries), and Santa Chiara, in Romanesque-Gothic-Aragonese style (16th century).