Fourteen species of Parioglossus are recognized from the warm temperate to tropical western Pacific and Indian Oceans: P. aporos n. sp., P. dotui, P. formosus, P. lineatus n. sp., P. marginalis n. sp., P. nudus n. sp., P. palustris, P. philippinus, P. rainfordi, P. raoi, P. taeniatus, P. triquetrus n. sp., P. verticalis n. sp., P. sp. Synonymies, general morphology and osteology of the genus are described, and a key for separating the species is included. Diagnoses, descriptions, distributions, comparisons, line drawings and photographs of each species are given as well as synonymies of previously described species. Notes on ecology and food preferences are included when known. Tables of meristics and morphometrics are included for the holotypes and for all other material. Different characteristics of the species are compared in a separate table. Similarities between Parioglossus and related genera, in the subfamily Ptereleotrinae, are discussed. Provisionally, the subfamily is placed in the family Microdesmidae.