A cusk-eel, known from the Galápagos Archipelago since 1905, which has remained undescribed, is herein formally named, Ophidion galapagensis Lea & Robins. The species is known from 10 collections, including material from Isla del Coco. The species is endemic to the Galápagos Archipelago-Isla del Cocos biogeographic complex and is compared to the seven known eastern Pacific ophidiine cusk-eels; its relationship to these species is unclear. It is distinguished by dorsal-fin ray, anal-fin ray, and vertebral counts, and the relationship of pelvic-fin filaments and pectoral-fin length. It is most frequently collected by ichthyocide from depths between 3-25 m and taken by bottom trawl to depths of 110 m. It is occasionally observed by scuba divers during night dives.