Neea gustaviaefolia, a new species from the wet forests from “Sierra de La Macarena” and upper “Guaviare” river regions of Colombia (Guaviare and Meta departments) is described, illustrated, and its morphological relationships are discussed. This new species is a small tree of 6 m tall, on the basis of its alternate, oblanceolate larger leaves and a shorter terminal cymes inflorescence, verticillate (with three opposite primary branches), it does not appear to be closely allied to any other Neea species. This new species shares several other features with five species (N. alumnorum, N. brevipedunculata, N. floribunda, N. itanhaensis and N. verticillata). Morphologically, however, it is comparable to N. alumnorum and N. itanhaensis but it differs in its leaves, inflorescences, staminal perianth, and stamens number. In addition, ecological, floristic, and geological notes about the “La Sierra de La Macarena are included. A key for identifying species of Neea to Colombia is also provided. Neea gustaviaefolia is remarkable for its alternate, larges leaves (30–65 × 10–20 cm), in an otherwise predominantly opposite, small to medium (4–25 × 2–8 cm) leaved genus, and it increases to 27 the number of species of the genus to Colombia flora.