Stenoninereis species are nereidids with a small body (ca. 35 chaetigers), dorsal cirri with conspicuous cirrophores and cirrostyles, bare pharynx, and lack of neuropodial ventral ligules throughout the body. Currently, there are two valid species, S. martini Wesenberg-Lund, 1958 from the Lesser Antilles and S. tecolutlensis de León-González & Solís-Weiss, 1997 from Eastern Mexico. Nicon lackeyi Hartman, 1958 has been regarded as a junior synonym of S. martini. The examination of type and topotype specimens indicated that N. lackeyi is a distinct species and both species are redescribed, S. martini is restricted to the Caribbean islands, and N. lackeyi is reinstated and transferred to Stenoninereis. Further, Puerto Rican specimens differ from these known species and a new species, S. elisae is also described, featured mainly by large cirrophores and short cirrostyles in anterior and middle chaetigers. Further discussions about their morphology and phylogenetic affinities and a key to identify all known Stenoninereis species are also included.