Rosthwaite is a settlement in the Borrowdale parish of Cumberland, Cumbria, England.

It is also in Borrowdale in the English Lake District to the south of Derwent Water.

Historically part of Cumberland, the nearest town to Rosthwaite is Keswick, which is situated approximately 6 miles (9.7 km) to the north.

Near to and within Rosthwaite is also a set of terminal moraines which show the staggered retreat of the Stonethwaite Glacier.

For Local Government purposes it is in the Keswick Ward of Cumberland Council.