Lake Šas (Serbian: Шаско jезеро, romanized: Šasko jezero; Albanian: Liqeni i Shasit) is a lake located north-east of Ulcinj, near the village of Šas, in Montenegro.

It is bordered geographically by Briska Gora (Mali i Brisë) to the southwest, Fraskanjelsko Polje (Këneta e Fraskanjellit) to the east, Ambulsko Brdo (Mali i Amullit) and Šasko Brdo (Mali i Shasit) to the northeast and the Brisko Polje (Fusha e Brisë) to the northwest.

Geopolitically, Briska Gora lies to the southwest of Lake Šas, Fraskanjel lies to the east and Ambula and Šas to the northeast.

In warmer months, the lake is populated with large numbers of different bird species.

List of bird species that have been found in Lake Šas: