This paper reviews all currently known records of copepod crustaceans of the family Lamippidae (Cyclopoida). The lamippids are highly modified endosymbionts found only on octocorals in the channels of mesoglea and gall-like proliferations of the host tissues. 54 species and 11 genera of copepods have been reported associated with 42 species, 33 genera and 18 families of the octocoral orders Alcyonacea and Pennatulacea. The highest numbers of records of lamippids living on octocorals have been reported among the diverse and common octocoral families Alcyoniidae, Gorgoniidae, Nephtheidae, Pennatulidae, and Plexauridae. Lamippids are better studied on more common octocorals from shallow depths and still comparatively poorly studied on octocorals from bathyal and abyssal depths. Lamippids have been recorded from 62 sites in 12 realms of the World Ocean and are comparatively better studied in the Northern Atlantic, Central Indo-Pacific and Tropic Atlantic; no lamippids have been reported so far from the Tropical Eastern Pacific, Temperate South America, South Africa, or Australasia. The data show that only approximately 1% of potential octocoral hosts have been explored thus far, showing a clear need for further integrative studies on this unusual group of symbiotic crustaceans.