The systematics of Western Australian members of Brown's (1810) genus Eriochilus R.Br. has been controversial, confused and poorly understood. This paper provides a revision drawing upon recent fieldwork, collections and herbarium studies that considerably resolve the taxonomic situation. We describe the following taxa as new: E. helonomos, E. pulchellus, E. valens, E. dilatatus subsp. magnus, E. dilatatus subsp. orientalis, E. dilatatus subsp. undulatus, and E. scaber subsp. orbifolia. New combinations are E. dilatatus Lindley subsp. multiflorus (Lindley) Hopper and A.P. Br. and E. dilatatus Lindley subsp. brevifolius (Benth.) Hopper and A.P. Br. The genus is thus enlarged in Western Australia to 6 species. E. dilatatus is geographically variable, now with six subspecies. E. scaber subsp. orbifolia is the only threatened taxon in Western Australia, known from a single locality near Walpole.