The Western Australian Kimberley region harbours a diverse fauna of camaenid land snails characterised by marked patterns of narrow range endemism. A recent survey of previously poorly known areas along the Kimberley coast has resulted in the discovery of a number of further, yet undescribed camaenid taxa. One of these, the genus Australocosmica, is newly described herein based on comparative studies of genital anatomy, shell and radular morphology, and analyses of partial sequences of the mitochondrial marker 16S rRNA. Australocosmica is characterised by a broadly conical to semi-globose shell with moderately elevated spire, well-rounded, convex whorls that are separated by a deeply incised suture, and a sculpture of dense, regularly spaced axial ribs. The most distinguishing feature of the inner penial anatomy is the presence of a furrowed, collar-like vergic papillum forming the entrance of the vas deferens into the lumen of the penial chamber. Three new species, Australocosmia augustae, A. sanctumpatriciusae, and A. vulcanica, are described based mainly on differences in penial anatomy. All species are well differentiated by uncorrected pair-wise p-distances of 15% to 20% in the 16S rRNA gene. Similar to most camaenids in the Kimberley region, species of Australocosmica are narrow-range endemics being restricted to single islands, sometimes including the immediately adjacent mainland coast.