Background and aims - The African genus Uapaca of the Phyllanthaceae (formerly Euphorbiaceae) is revised for the Flore du Gabon. Prior to its publication, the present paper publishes a new species from that country. Methods - Normal practices of herbarium taxonomy have been applied to study all herbarium material available mainly at BR, K, LBV, MO, P, WAG. Key results - The new species Uapaca niangadoumae belongs to the group of Uapaca species that lack stipules or have rudimenary stipules only. A key to these species is provided. The new species is illustrated.