Holkham National Nature Reserve is England's largest national nature reserve (NNR). It is on the Norfolk coast between Burnham Overy Staithe and Blakeney, and is managed by Natural England with the cooperation of the Holkham Estate. Its 3,900 hectares comprise a wide range of habitats, including grazing marsh, woodland, salt marsh, sand dunes and foreshore. The reserve is part of the North Norfolk Coast Site of Special Scientific Interest, and the larger area is additionally protected through Natura 2000, Special Protection Area (SPA) and Ramsar listings, and is part of both an Area of Outstanding Natural Beauty (AONB) and a World Biosphere Reserve. Holkham NNR is important for its wintering wildfowl, especially pink-footed geese, Eurasian wigeon and brant geese, but it also has breeding waders, and attracts many migrating birds in autumn. Many scarce invertebrates and plants can be found in the dunes, and the reserve is one of the only two sites in the UK to have an antlion colony.

Holkham is a small village and civil parish in north Norfolk, England, which includes a stately home and estate, Holkham Hall, and a beach, Holkham Gap, at the centre of Holkham National Nature Reserve.