Chew Magna Reservoir is a 5-acre (2 ha) reservoir on the western outskirts of the village of Chew Magna, Somerset, England.

The reservoir was created by damming Winford brook in order to supply water for villages in the Chew Valley.

Chew Magna reservoir provides fly fishing for stocked brown trout (Salmo trutta morpha fario) and rainbow trout (Oncorhynchus mykiss).

In 2011 the reservoir emptied following a long period without sustained rainfall.

Bristol Water rescued the trout and transferred them to the nearby Chew Valley Lake.