The first revision of the Neotropical woody bamboo genus Colanthelia is here presented. Updated morphological descriptions of the species, comments, illustrations, and keys to the species (one based on vegetative characters only and the other based on vegetative plus reproductive characters) are provided. Colanthelia consists of nine species, all characteristic of the Atlantic forest habitat, three of which are described and illustrated as new in this treatment: C. kinoshitae, which has fimbriate auricles on the apex of both the culm and foliage leaf sheaths and adaxially glabrous to glabrate culm leaf sheaths and glabrous girdles; C. secundiflora, characterized by its erect culm leaf blades, secund spikelets, and the lemmaswith dark spots; and C. sparsiflora, which has synflorescences with spikelets widely separated from each other. Eight species are endemic to Brazil and one, C. rhizantha, is found in both Brazil and Argentina. Colanthelia distans and C. macrostachya are probably extinct. Colanthelia lanciflora, originally described as a species of Aulonemia, is here excluded from Colanthelia, and reassigned to Aulonemia.