Grey Wethers consists of a pair of prehistoric stone circles, situated on grassy plateau to the north of Postbridge, Dartmoor, in the United Kingdom.

The northern circle has 20 stones remaining, while the southern has 29 – all of a relatively consistent size, mostly between 1.2 and 1.4 m (3.9 and 4.6 ft) in height.

As with many ancient Dartmoor landmarks, Grey Wethers is the subject of local folklore, explaining the origin of the name ('wether' is an Old English word meaning sheep).

One story tells of a farmer who had recently moved to Dartmoor and was foolish enough to criticise the sheep on sale at Tavistock Market.

He stopped for a drink at the Warren House Inn, and helped by several pints of cider, the locals persuaded him that there was an excellent flock of high quality sheep nearby which he would be welcome to buy.