The Muscidae (Diptera) of Namibia were previously known to comprise 42 species in 16 genera. The study of material from the Namibia National Insect Collection, National Museum of Namibia and the Albany Museum (South Africa) loaned to the authors enabled this paper to be written, in which three new generic records and 14 new species records are provided and one new species is described. With the present contribution, the muscid fauna of Namibia is now known to comprise 57 species in 19 genera, with Musca L. being the most species-rich genus. A key to the identification of all recorded genera is provided and diagnoses of the genera and species found in the material studied are provided when pertinent. Musca fragilis sp. n. is described from the Khorixas District.