Historically, taxonomic delimitation of Mandevilla Lindley, a large Neotropical genus of Apocynaceae, has been controversial. Two competing classifications were proposed by Woodson (1933) and Pichon (1948), the former now being widely accepted by taxonomists in the family. Recent phylogenetic studies, however, support the monophyly of Mandevilla sensu Pichon rather than sensu Woodson, the latter being paraphyletic with respect to Quiotania Zarucchi, Macrosiphonia Müller Argoviensis, and Telosiphonia (Woodson) Henrickson. Based on the principle of monophyly, we here re-establish Pichon's classification and include Quiotania, Macrosiphonia, and Telosiphonia as synonyms of Mandevilla. Three new combinations are made here: Mandevilla hesperia (I. M. Johnston) A. O. Simões, L. S. Kinoshita-Gouvêa & M. E. Endress, M. nacalpulensis (Felger & Henrickson) A. O. Simões, L. S. Kinoshita-Gouvêa & M. E. Endress, and M. undulata (C. Ezcurra) A. O. Simões, L. S. Kinoshita-Gouvêa & M. E. Endress; Q. colombiana Zarucchi is newly synonymized with M. ligustriflora Woodson; and a lectotype is designated for M. martii (Müller Argoviensis) Pichon.