Crassothonna agaatbergensis, here described as a new species, is known only from the northern part of the Skeleton Coast (part of the Namib Desert) in the Kaokoveld Centre of Endemism, northwestern Namibia. These perennial shrublets grow on basalt of the Agaatberg Mountain under harsh desert conditions. Diagnostic characters for C. agaatbergensis include the partially buried, globose, obovoid or ampulliform caudex and the inconspicuous rays which are much shorter than the involucre. A comparison of some of the more prominent morphological features to differentiate between C. agaatbergensis and its possible nearest relatives, C. clavifolia and C. protecta, is provided. Based on IUCN Red List categories and criteria, a conservation assessment of Endangered (EN D) is recommended for the new species. Keywords: Agaatberg, endemism, flora, Gariep Centre of Endemism, Kaokoveld Centre of Endemism, Namib Desert, succulent, taxonomy.