The genus Calycolpus (Myrtaceae), a mainly northern South American group of 15 species, is revised based on a study of over 600 plant collections, many duplicated in more than one herbarium. The relationships of Calycolpus to other genera are discussed and a key distinguishing it from its relatives is provided. All species are described, mapped, and illustrated with line drawings and/or photographs. The relationships among the species are discussed and a key distinguishing them is provided. Lectotypes are chosen for Myrtus goetheana DC., Calycolpus chnoiophyllus Riley, Calycolpus cordatus L. Riley, Calycolpus kegelianus O. Berg, Calycolpus schomburgkianus var. speciosus O. Berg, Eugenia excisa Urb., Eugenia nipensis Urb., Psidiopsis moritziana O. Berg, and Psidium reversum Urb. Neotypes are chosen for Calycolpus kegelianus var. gracilis O. Berg, Calycolpus warszewiczianus O. Berg, and Myrtus revoluta Schauer. Five of these species, one third of the total, were described by the author since 1989.