Triplectides itatiaia sp. nov. is described from specimens collected on the Itatiaia massif, Mantiqueira mountain range, Rio de Janeiro state, Brazil. The new species can be distinguished by the presence of hind wing fork I petiolate, the long dorsal excision of segment X and the flat, apically rounded mesal lobes. Female and immature stages are unknown. A key to the Brazilian species in the genus is provided.