Seat Sandal is a fell in the English Lake District, situated four kilometres (2+1⁄2 miles) north of the village of Grasmere from where it is very well seen.

The fell's western flanks above Dunmail Raise are grassy and smooth while its eastern slopes are steep and craggy as they fall away towards Grisedale Hause which at 537 m (1,762 ft) contains Lakeland's highest substantial tarn, Grisedale Tarn.

Seat Sandal is distinctive in that its drainage reaches the sea at more widely spread points than any other Lakeland Fell, with Raise Beck going through Thirlmere and Derwent Water to reach the Irish Sea at Workington, Tongue Beck going through the lakes of Grasmere and Windermere to reach Morecambe Bay and Grisedale Beck draining into Ullswater and then to the sea at the Solway Firth.

A hill of andesite lava forms the summit, the rocks beneath being the dacitic lapilli-tuffs of the Lincomb Tarns Formation.

[1] The fell can be ascended from Grasmere or Dunmail Raise although a start from Patterdale is quite feasible.