The separation of Thecacoris and Cyathogyne (Phyllanthaceae, formerly Euphorbiaceae) is discussed and it is concluded that they should remain united. A separation of the continental forest species (except Thecacoris viridis (Müll.Arg.) Leandri ex G.L.Webster) awaits molecular investigation. Thecacoris micrantha sp. nov. is described and illustrated. Thecacoris grandifolia (Pax & K.Hoffm.) Govaerts from Cameroon is neotypified. Thecacoris membranacea Pax and T. annobonae Pax & K.Hoffm. are lectotypified and placed in synonymy under T. stenopetala (Müll.Arg.) Müll.Arg. and T. trichogyne Müll.Arg., respectively. Thecacoris manniana (Müll.Arg.) Müll.Arg. is united with T. stenopetala under the latter name. A key to and a synopsis of the West African species is provided.