The freshwater crayfish genus Parastacoides Clark, 1936 was last reviewed by Sumner (1978). In that review Sumner synonymised several species, reducing the genus to one species, consisting of three subspecies. However, subsequent collections of specimens from previously unsurveyed areas, as well as field studies on habitat partitioning by the subspecies, cast doubt on the taxonomic status that Sumner proposed. Molecular studies suggesting the presence of several genetically distinct populations provided the stimulus for this review. A complete revision of the genus has led to the recognition of two new genera and 14 new species. Keys, descriptions, diagnoses, synonymies and distribution maps of the genera and species are provided. During the course of this study it was discovered that the type specimen attributed to the genus Parastacoides is a specimen of the genus Geocharax Clark, 1936. The name Parastacoides is a junior synonym of Geocharax, and new names for the genera previously described as Parastacoides have been raised.