The Bonaparte Gulf Basin contains Palaeozoic rocks covering about 8000 square miles of land around the Joseph Bonaparte Gulf (Fig. 1); the larger part of the basin lies beneath the Timor Sea. Its landward part is truncated by a northeasterly fault zone from Precambrian rocks on the east; the southwestern margin overlaps Precambrian rocks of the Kimberley Block. The estuary of the Victoria River (Queens Channel) separates the landward part of the basin into two areas of outcrop-the southwestern area with Cambrian, Ordovician, and Devonian to lowermost Permian outcrops, and the northern part with Permian, possibly Lower Triassic, and Lower Cretaceous outcrops. This Bulletin describes the ostracods In the Upper Devonian fauna of the Bonaparte Gulf Basin, assesses their stratigraphical value, and is a part of the overall study of the Upper Devonian and Lower Carboniferous geology and palaeontology; it also represents the first taxonomic and biostratigraphic study of Upper Devonian Ostracoda from Australia.