A revision of Trachyloma Bridel based upon study of specimens from throughout the known range of the genus shows it to consist of five species: T. indicum (Indomalaya and adjacent areas, Oceania), T. diversinerve (Australia, New Zealand, New Caledonia), T. planifolium (Australia, New Zealand), T. Wattsii (Lord Howe Island), and a new species from Mount Wilhelm, Papua New Guinea. The type species of the genus, T. planifolium, is neotypified. Trachyloma novae-caledoniae is recognized as a synonym of T. diversinerve, and T. indicum is divided into four varieties, three of which are newly proposed. Scanning electron microscopy of spores, calyptrae, and peristomes illustrates the taxonomic value of these structures. The stenotypic peristomes consist of 16 exostome teeth (outer surfaces uniformly papillose) and 16 alternating endostome segments that arise from a high basal membrane. Other newly recognized taxonomic characters include location, size, and presentation of gemmae, form and number of paraphyses per perichaetium, and nature of the exothecial wall thickenings. Trachyloma is retained within the Pterobryaceae, subfamily Trachylomoideae, but this assignment is one of expediency.