The Alvinellidae are a family of small, deep-sea polychaete worms endemic to hydrothermal vents in the Pacific Ocean. Belonging to the order Terebellida, the family contains two genera, Alvinella and Paralvinella; the former genus contains two valid species and the latter eight. Members of the family are termed alvinellids.The family was first described in 1979 after discoveries made off the Galápagos Islands by the crew of the DSV Alvin.