A new species of Terminalia L. (Combretaceae) from the Guiana shield is described as T. carinata Sabatier & J.Engel, sp. nov. based on morphological evidences. This new species was often misidentified as T. guyanensis Eichler from which it differs, as well as from other neotropical Terminalia, by its leaf undersurface palish-gray and slightly pubescent, quite long petioles and fruits with two wings wider than the body that is distinctly keeled on one face and flat on the other. An updated description of T. guyanensis is provided and the conservation status of T. carinata Sabatier & J.Engel, sp. nov. and T. guyanensis is evaluated according to IUCN criteria and a status of Least Concern (LC) is proposed for these two species.