A new species, Lellingeria cantarensis, is described from the cloud forests of Cerro Jefe, an isolated mountain peak in central Panama known for its high levels of endemism and species diversity. It appears most similar to L. kaieteura and L. epiphytica, both of which also have dorsiventral rhizomes, clathrate rhizome scales with ciliate margins and abaxial hairs on the rachis. The new species is distinct from those two species, and from all other congeners, by its small laminae (less than 6 cm long), truncate laminar base, and the abaxial side of rachis is densely pubescent. Lellingeria subimpressa is also similar to L. cantarensis but it differs by having a glabrous rachis. None of the similar species are sympatric with L. cantarensis; they are restricted to Costa Rica, South America, or Caribbean Islands. A phylogenetic analysis using five plastid markers and 94 other grammitid taxa confirms the new species as sister to the Lellingeria suprasculpta clade with strong support. Lellingeria cantarensis is known only from the type and one additional collection from the type locality, and it is one of ten Lellingeria species found in Panama; it is also the only endemic Lellingeria in the country. We also provide a key to the species that occur in Panama and neighboring Costa Rica. With the addition of this new species, the total number of Lellingeria species becomes 51 worldwide.