A new species of Alcyonosyllis (Polychaeta: Syllidae), A. hinterkircheri, is described from a scleractinian coral, Goniopora' cf. 'stokesi Edwards and Haime (Poritidae) from shallow coastal waters near Bohol Island, Philippine Islands. It represents the first record of an Alcyonosyllis species on a scleractinian coral and the first record of a commensal polychaete on a Goniopora species. The new polychaete differs from other described species of Alcyonosyllis in having long, slender dorsal cirri exhibiting a strong, long-short alternation pattern over the entire body; in its olive-green colour pattern; and that all chaetae are unidentate. Also, new records of the type species of the genus, 'A. phili', from Australia and the Philippine Islands extend the known range of this species. Lastly, a possible new species from Sumba, Indonesia similar to 'A. xeniaecola' (Hartmann-Schroder, 1993) is mentioned but not formally described because only one specimen is known to date. A dichotomous key is provided to distinguish the seven species known with certainty in the genus.