Lethacotyle fijiensis Manter & Prince, 1953 is a species of monogenean of the family Protomicrocotylidae. The species is ectoparasitic on the gills of an unknown carangid fish identified in the original publication as "yellow jack". It is the type-species of the genus Lethacotyle Manter & Prince, 1953. It has been described from two specimens only by Manter & Prince in 1953; of these, a single specimen, the holotype has been kept in the US National Parasite Collections and thus was the single specimen of the species, and therefore of the genus, which was available for study. Later, another species of the same genus was described.