Taxonomy of Smilax in the Neotropics is poorly known with many undescribed species, unresolved synonymy, and regional treatments with conflicting taxon concepts. This issue is amplified in the Guiana Shield, which has arguably received the least amount of taxonomic research in Smilax. Here, we investigate multiple specimens from Tafelberg, Suriname that we hypothesized to represent an undescribed species. We used univariate and multivariate morphometrics to analyze linear measurements and leaf outlines to test if and how Tafelberg specimens differ from those of morphologically similar species in the Guiana Shield, Smilax lasseriana and S. maypurensis. We used a genome skimming approach to sequence and assemble plastomes, which also allowed us to extract plastid loci previously employed in Sanger-based studies and place the putative new species in a phylogeny with expanded taxon sampling. We recovered the Smilax from Tafelberg as more closely related to species with ranges centered in eastern Brazil than to its morphologically hypothesized congeners, S. lasseriana and S. maypurensis. We describe this new species as Smilax tafelbergensis with detailed morphological comparisons to similar taxa, a distribution map, and illustration.