The Réunion greeneye Chlorophthalmus vulcanus n. sp. is described from La Réunion, southwestern Indian Ocean, based on a specimen collected in 2003 off the west coast of the island at 300-400 m depth. The species is characterized by the combination of the following characters: total dorsal-fin rays 11, total anal-fin rays 8; total pectoral-fin rays 15; hump absent before dorsal fin; one small, rounded projection on lower jaw symphysis; teeth on outmost patches of lower jaw very small; teeth on tongue absent; gill rakers 4+18; head length 31.3% of SL; snout length 8.3% of SL; horizontal orbit diameter 12.3% of SL; snout length in horizontal orbit diameter 1.5; upper jaw length 12.6% of SL; predorsal fin length 36.5% of SL; prepectoral fin length 32.1% of SL; lateral-line scales 57; scale rows above lateral line 5; pectoral-fin length 30.4% of SL; first pelvic-fin ray situated under 6th dorsal-fin ray. An identification key to the species of Chlorophthalmus is presented.