A new species, Oxyanthus andjigae Sonké & O. Lachenaud (Rubiaceae), from Ivory Coast and Sierra Leone, is described and illustrated. It is closely related to Oxyanthus racemosus (Schumach. & Thonn.) Keay and Oxyanthus setosus Keay, and was previously confused with the latter species; however, it differs from both in the longer corolla tube (18–19.5 cm vs (7-)11-15.5 cm) and the longer hairs on the twigs (1.5–2 mm long vs. ≤ 1 mm in Oxyanthus setosus and ≤ 0.5 mm in Oxyanthus racemosus). From Oxyanthus setosus it is also separated by the distribution, the latter species occuring from Nigeria to Gabon. The species is assessed as “Endangered” following IUCN Categories and Criteria. A new identification key to West African species of Oxyanthus DC. is presented; Oxyanthus oliganthus K. Schum. is newly reported from Côte d'Ivoire and Ghana.