Parabuthus muelleri Prendini, sp. nov. is described and figured, based on two female specimens collected during a recent field trip to Namibia. The male is currently unknown. This new species is shown to be most closely related to Parabuthus capensis (Ehrenberg), a common, widespread species south of the Orange River (in South Africa). Meristic data for both the above species are tabulated, and a distribution map illustrates the range of P. capensis, including the first confirmed records of that species from north of the Orange River (in Namibia). An appendix lists all additional material examined.