Lake Coghinas (Italian: Lago di Coghinas) is an artificial lake, in northern Sardinia, Italy, located between the provinces of Sassari and Olbia-Tempio. With a surface of 17.8 km² and a capacity of 254 millions cubic metres of water, it is the second largest lake in the region (second only to Lake Omodeo) and one of the major reservoirs in Italy.
The dam, constructed under Fascism in 1924, is 185 metres long and 58 metres wide. It has the function of water supply, but also it has a hydroeletric power plant.
The lake is the home of a rich ecosystem, and it is become a tourist attraction, around its shores are present a youth hostel, restaurants, a sailing club.