A taxonomic revision of Oreorchis is presented. A key to the species and synonymies, descriptions, illustrations and distributions for each taxon are provided. The status of the genera Kitigorchis F. Maek. and Diplolabellum F. Maek. are discussed. The former is redefined as a monotypic genus, with three of the four species included by Maekawa being returned to Oreorchis; the latter is considered congeneric with Oreorchis. Three species, O. angustata, O. aurantiaca and O. nepalensis, are newly described here and O. indica is reduced to varietal status within O. foliosa. Some outstanding problems in the taxonomy of the genus are noted.
