The caprellidean fauna of Western Australia and Northern Territory, Australia, is investigated here. The study reports 26 species in 19 genera. Six new species (Aciconula australiensis n. sp., Caprella traudlae n. sp., Pseudaeginella vaderi n. sp., Orthoprotella nana n. sp., Pseudoprotella soela n. sp. and Pseudoprotomima grandimana n. sp.) are described as new for Science. Lateral view figures of all the species, together with a key to species level, are also provided.