The vegetation of the Kalahari Gemsbok National Park, which lies in the centre of the semi-arid Southern Kalahari, was studied. This area is considered to be largely representative of the Southern Kalahari in general. The region is covered by a layer of red sand piled into dunes. Two large dry river-beds cross the area and numerous pans occur. Calcrete outcrops are found along rivercourses and around pans. The vegetation is generally an extremely open shrub or tree savanna and phytogeographically the area is regarded as belonging to the Karoo-Namib Region. 132 quadrats, most of which covered 100 m2, were studied and the vegetation is classified according to the Zürich-Montpellier method. The physiognomy of all phytocoenoses was determined according to the system ofFosberg (1967). A striking correlation was found between plant communities and the four main habitats: sand, calcrete, pans and river-beds. Twelve syntaxa were recognized, eight of these are described as associations and one as a subassociation.