The genus Hermeuptychia is common and widespread through the Americas, from Argentina to the southern United States of America. All eight recognized species within Hermeuptychia are small and brown, with very similar interspecific external morphologies and intraspecifically variable ocelli patterns that render taxonomic identification based on morphology difficult. In our study, we surveyed variability within Hermeuptychia, and evaluated species boundaries based on molecular data (sequences of the ‘barcode’ mitochondrial DNA COI gene) and morphology (mainly male genitalia), using a phylogenetic approach. We found eight DNA-based and 12 morphological groups in our sampling. Species names were assigned based mainly on comparisons with male genitalia morphology descriptions corresponding to name-bearing type specimens. Morphological and DNA variability were highly congruent, with the exception of group H, the Hermeuptychia cucullina complex. Also, the barcode region showed a clear threshold for intra- and interspecific mean distances around 2%. Based on these results, we circumscribe the species boundaries in the genus Hermeuptychia and discuss conflicts between mitochondrial genes and classic morphological approaches for identifying and delimiting species. Our study revealed cryptic diversity within an ubiquitous genus of Neotropical butterflies.