Calthorpe Broad is an isolated broad within The Broads National Park, three miles north east of Stalham, Norfolk, England.

English Nature manages it as a National Nature Reserve, one of over 200 NNRs. It is only 44 hectares, but of interest because of its plantlife. It is detached from the main network of broads and rivers, but is part of the River Thurne catchment area.