The Natalimyzidae, a new African family of acalyptrate Diptera in the superfamily Sciomyzoidea, is established for Natalimyza gen. n. and a single new species, namely N. milleri, from Van Reenen's Pass and Giant's Castle Game Reserve in the KwaZulu-Natal Drakensberg mountain range, South Africa. The family is, however, known to be widespread in Africa, with current records being South Africa (Western Cape, Eastern Cape, KwaZulu-Natal, Mpumalanga, Limpopo), Zimbabwe, Kenya and Nigeria. Natalimyzidae are mainly found in grassland, and in South Africa the family is most often collected during the dry, winter months in the eastern summer rainfall region. The larvae appear to be microflora grazers on decaying grass. Numerous additional new species of these small flies (approx. 2.5-4.5 mm long) await description; a likely total of more than 30 species could be expected. The Natalimyzidae is the first widespread new family of Diptera described entirely from new African taxa. The relationships of Natalimyza with other schizophoran superfamilies are discussed, and the genus is referred to the Sciomyzoidea. A detailed review of all families of Sciomyzoidea suggests no definite sister group relationship with Natalimyza, and the new family is provisionally treated as incertae sedis within the superfamily. KEY WORDS: Diptera, Schizophora, Sciomyzoidea, Natalimyzidae, new family, Africa, grassland.