A cladistic analysis was performed on 49 species (known and unknown) of the genus Neocorynura (Hymenoptera: Halictidae), based upon 187 characters, most of them from adult morphology. Outgroups consisted of 13 species, some of them belonging to other genera of augochlorines believed to be closely related to the genus Neocorynura. The analysis showed the monophyly of the genus Neocorynura when the species belonging to the genera Andinaugochlora and Neocorynurella were included. The resulting phylogenetic tree showed four main clades (species groups) within the genus, of them the most basal ones corresponding to some of the species of Andinaugochlora and Neocorynurella . The systematics of the genus Neocorynura is discussed, a new diagnosis and the resulting changes in the classification of the genus Neocorynura are included. All four major species groups are discussed and diagnosed, and keys to separate them are provided. Some comments on the biogeography, and biology of the genus (including the apparent mimicry among some of the species) and the relations with the phylogeny are presented.