Potaro-Siparuni (Region 8) is a region of Esequiban Guyana, a territory in dispute by Guyana and Venezuela. Venezuela claims the territory as part of Bolívar state. The regional capital is Mahdia.
The region is in the west of the country. It has an area of 20,051 km². As of the 2012 census, 10,190 people lived there. It borders the region of Cuyuni-Mazaruni to the north, the regions of Upper Demerara-Berbice and East Berbice-Corentyne to the east, the region of Upper Takutu-Upper Essequibo to the south and Brazil to the west.