A new species of triplefin blenny, Helcogramma atauroensis, from Timor-Leste is described on the basis of eight specimens. The new species is characterized within the H. steinitzi species complex by having 14–15 second dorsal-fin spines, 9–11 third dorsal-fin rays, one symphyseal mandibular pore (total pores 9–11), the nape without scales, 19–23 tubular pored lateral-line scales, the head profile about 70º to horizontal, the first dorsal fin beginning above the preopercle, the anal fin in male red without melanophores, the female with six oblique bars, and a black pelvic fin in males. Revised keys to the H. steinitzi species complex and to all members of the genus in the western Pacific Ocean and Indo-Australian Archipelago are presented.