Cuyuni-Mazaruni (Region 7) is a region of Esequiban Guyana, a territory in dispute by Guyana and Venezuela. Venezuela claims the territory as part of Delta Amacuro state north of the Cuyuni river and as a part of Bolívar state south of the same river. The regional capital is Bartica.
The region is in the west of the country. It has an area of 47,213 km². As of the 2012 census, 20,280 people lived there. It borders the regions of Barima-Waini, Essequibo Islands-West Demerara and Pomeroon-Supenaam to the north, the region of Upper Demerara-Berbice to the east, the region of Potaro-Siparuni, Brazil to the south and Venezuela to the west.