The phyline fauna of Australia has only recently been shown to be highly diverse, both at the species and the genus levels. Here, a new genus and four new species of Australian Phylinae (Hemiptera: Miridae) are described. The species of Restiophylus, n. gen., occur on two genera of the rush-like Restionaceae, Hypolaena Brown 1810 and Leptocarpus Brown 1810, and on one genus of the closely related Anarthriaceae, Lyginia Brown 1810. Habitus images, illustrations of male genitalia, scanning micrographs, an identification key, and distribution maps for the new species are provided as well as digital images and distribution maps for the hosts. Consistent with the geographic distribution patterns of many other Australian Phylinae, the four new species are restricted to the Mediterranean-type biome of Western Australia. A cladistic analysis based on 55 morphological characters, four ingroup taxa, and 31 outgroup taxa is presented, providing evidence for the monophyly of this new genus and its placement in the tribe Semiini, and potentially as sister to the subtribe Exocarpocorina.