I present a phylogeny of the Latin American snake genus Chironius based on 36 external morphological and hemipenal characters. Data from the literature for the 20 recognized species of Chironius were combined with data I collected from 20 outgroup taxa. I assessed the monophyly and in-group relationships of Chironius using both parsimony and methods. Two optimal trees were obtained using parsimony criteria; the genus Chironius is supported as monophyletic with 93% bootstrap support from six unambiguous synapomorphies, including an even number of scale rows at midbody. A Bayesian analysis of the data supports the monophyly of Chironius with a posterior probability of 100%. Both analyses inferred similar topologies; recognized species groups are partially supported, but this analysis suggests that revision of the genus is necessary. I propose elevation to full species status of taxa within the carinatus, fuscus, multiventris, and quadricarinatus species groups on the basis of morphological features unique to each taxon. Future molecular work is necessary to resolve the remaining taxonomic issues within Chironius.