Mysmenopsis is a kleptoparasitic genus of tiny tropical and subtropical American spiders in the family Mysmenidae. Most live in the funnelwebs of spiders in the family Dipluridae. M. archeri lives on webs of a species in the family Pholcidae, M. capae and M. cienga have been observed living in Cyrtophora (Araneidae) webs. One reason why diplurid webs are preferred seems to be that they are persistent in time and space, sometimes spanning several years. The monotypic genus Isela is closely related.