Heteromys anomalus is widely distributed along the Caribbean coast of South America and had been considered the only spiny pocket mouse present in Venezuela for several decades. Recent taxonomic studies in western Venezuela, however, have documented the presence of H. australis from the Cordillera de Mérida and described H. oasicus from the Península de Paraguaná. Here, we revise the genus Heteromys in central and eastern Venezuela as well as in Trinidad and Tobago. Morphological comparisons with samples of H. anomalus from throughout its known range in Venezuela and with representatives of all other recognized species of the genus indicate the existence of a species new to science, which we describe as Heteromys catopterius (the Overlook Spiny Pocket Mouse). This species ranges from 350 to 2425 m in elevation in the Cordillera de la Costa in northern Venezuela, with the vast majority of records above ca. 700 m. In central and eastern Venezuela, H. anomalus is found in the surrounding lowlands and lower slopes of the Cordillera. Externally, H. catopterius is darker than H. anomalus and lacks the distinctly rounded ears of that species. The new species averages larger than H. anomalus for most external and cranial measurements. Cranially, the two species have differences in proportion; the skulls of H. catopterius are proportionately wider (less elongated) than those of H. anomalus, with a relatively wider interorbital constriction, wider interparietal, and more inflated braincase. Heteromys catopterius occurs in wet montane forests (especially cloud forests) in four highland areas of the Cordillera de la Costa: the main Aragua-Carabobo chain, the El Ávila massif, the Serranía del Interior, and the Macizo Oriental. Presumably, the warm, dry lowlands of the Depresión de Unare represent a barrier for the species, separating populations in the Macizo Oriental from the more westerly populations. Large areas of the known ranges of both H. catopterius and H. anomalus are protected in the Venezuelan network of protected areas.