The genus Acnephalomyia Londt, 2010 (Diptera, Asilidae, Willistonininae) is re viewed in the southern Namib Desert. Currently, seven species of Acnephalomyia are recognised from Namibia and South Africa. In the southern Namib Desert, there are four Acnephalomyia species recorded to date: Acnephalomyia andrenoides (Wiedemann, 1828), Acnephalomyia eremia Londt, 2010, Acnephalomyia iota Londt, 2010 and Acnephalomyia platygaster (Loew, 1858). One new species, Acnephalomyia metallicoindica sp. nov. from the northern parts of the southern Namib Desert, is described and the single paratype of Acnephalomyia iota known from Namibia is assigned to this species, restricting A. iota to the Northern Cape Province of South Africa. Acnephalomyia eremia is recorded with several additional collecting events in the southern Namib Desert, extending its range significantly. Distribution, biology, occurrence in biodiversity hotspots sensu Conservation International and seasonal imago flight activity are discussed for each species. Diagnoses, photographs, specimen occurrence data and an identification key to species are provided with the new species described in detail. Online resources to the original descriptions or re-descriptions and an illustrat ed dichotomous identification key are provided and all specimen images are uploaded to a dedicated image repository. The southern Namib Desert is chiefly outlined by the Namib-Naukluft National Park and adjacent areas to the east using nature reserves and roads to delimit the study area more precisely. The knowledge of Diptera, Asiloidea species and important early collectors of specimens (including the museum depository), especially at the Gobabeb Namib Research Institute, is summarised. An updated key to the Asilidae genera of the Afrotropical Region, to include all species of Acnephalomyia, is provided. Both keys are made available online on the Lucid Keyserver. Keywords: Afrotropical, Namib Desert, robber fly.