Abstract:The triplefin genus Enneapterygius Rüppell, 1835, recored from the coastal waters of Taiwan is reviewed. There are eighteen valid species and eleven of these species have been collected for both molecular and morphological studies. A molecular phylogenetic analysis based on the partial sequence of mtDNA ND5 gene (about 1,000 bp) supports the valodity of each examined species of Enneapterygius and some groups shared similar branch lengths with varied bootstrap support, the possibility of repid evolutionary radiation within Enneapterygius is suggested. The combination of morphological and molecular analyses confirm that some synonymies occur and that the validity of specific names should be reconsidered. Enneapterygius rubicauda Shen & Wu, is a junior synonym of E. flavoccipitis Shen & Wu. Three recently-described species: E. erythrosomus Shen & Wu, E. hsiojenae Shen & Wu, and E. leucopunctatus Shen & Wu are considered to be valid species. Two new species, E. shaoi and E. sheni, are described herein. A diagnostic key to all recorded species of Enneapterygius in Taiwan is provided.