Cryphonectria is a fungal genus in the order Diaporthales. The most well-known and well-studied species in the genus is Cryphonectria parasitica, the species which causes chestnut blight. The genus was, for a time, considered synonymous with Endothia, but the two are now recognised as distinct. Taxonomic studies in 2006 limited the genus to four species, but a fifth, Cryphonectria naterciae, was described in 2011 from Portugal.