A revision of the genus Echidnopsis Hook.f. (Asclepiadaceae). The tropical north-east African and Arabian genus Echidnopsis is revised to include Pseudopectinaria. Nineteen species are recognised and they are grouped into four new sections. The new taxa E. scutellata subsp. dhofarensis and E. scutellata subsp. australis are published and four new combinations are made: E. scutellata subsp. planiflora, E. sharpei subsp. ciliata, E. sharpei subsp. repens, and E. malum. The following species are accepted: E. angustiloba, E. archeri, E. ballyi, E. bihendulensis, E. cereiformis, E. dammanniana, E. ericiflora, E. insularis, E. leachii, E. malum, E. mijerteina, E. montana, E. scutellata, E. seibanica, E. sharpei, E. squamulata, E. urceolata, E. virchowii, and E. watsonii. Descriptions, illustrations and distributional data are provided for all the taxa recognised.