A new freshwater crab species of Liberonautes Bott, 1955 from Mt. Tonkori in the Upper Guinea rainforest in Côte d'Ivoire, West Africa is described. Liberonautes constantini n. sp. is morphologically distinct from other species of this genus found in Côte d'Ivoire and the neighboring countries. The new species is recognised by a unique combination of morphological characters of the carapace, thoracic sternum, major cheliped, and adult male first gonopod. Illustrations of L. constantini n. sp. are provided and differences from congeners found elsewhere in West Africa are discussed. The addition of L. constantini n. sp. raises the number of species of freshwater crabs known to occur in Côte d'Ivoire to seven. An updated checklist and key are provided to the Ivorian species of freshwater crabs, and their conservation status is discussed.