The present work deals with the 99 species of Notodontidae (but excludes the Thaumetopoeidae), so far recorded in the Republic of South Africa and the kingdoms of Swaziland and Lesotho. Twelve species and two subspecies are described as new from this area; three new genera are erected: Postscrancia gen. nov. with type species Scrancia discomma (Jordan, 1916), Archistilbia mlawula spec. nov., Afroplitis sulaki spec. nov., Desmeocraera hattinghorum spec. nov., Desmeocraera distanti spec. nov., Desmeocraera bethunebakeri spec. nov., Rhenea michii spec. nov., Rhenea kruegeri spec. nov., Zuluana gen. nov. with type species Sarimarais quarta (Kiriakoff, 1962), Speideliana gen. nov. with type species Speideliana maget spec. nov., Speideliana erichkaestneri spec. nov., Batempa mutabilis spec. nov., Janthinisca joannoui spec. nov., Clostera dukeorum spec. nov., Phyllaliodes agramma phyllaliodes subspec. nov., Eutimia gallans obscura subspec. nov. 22 taxa on generic level and 44 taxa on species–group level are downgraded to synonymy. 39 taxa are newly combined. Three genera are revitalized and in a further seven cases the status of the taxon on specific level was changed. To stabilize the nomenclature eight lectotypes are designated: Desmeocraera hierax Distant, 1897, Hoplitis concolor Janse, 1920, Eurystaura brunnea Janse, 1920, Eurystaura olivacea Gaede, 1928, Rigema woerdeni orientalis Strand, 1912, Rigema woerdeni meridionalis Strand, 1912, Antheua insignata Gaede, 1928, and Nunua gallans Karsch, 1895. All taxa treated in this monograph are illustrated in colour using type specimens wherever possible, as well as in series of adults to show individual variation. As a tribute to E. E. Platt, an early pioneer of South African Lepidopterology, images of blown caterpillar skins preserved in his collection are included on the coloured plates. Further plates show the genitalia of both sexes. For each species data about its bionomy including larval host-plants of the caterpillars are provided. The distribution of the South African Notodontidae is presented on dot-distribution maps, which include the entire southern Africa, north to the Zambesi river. The study area contains 24 endemic species and three species, which are represented by endemic subspecies. By courtesy of the Caterpillar Rearing Group of the Lepidopterists‘ Society of Africa (www.lepsoc.org.za/projects/crg) it was also possible to add some colour plates showing the early stages, living adults and some habitats of Notodontidae from South Africa.