蜡虫——又名蜡蚓——是螟蛾（主要是小蜡螟及大蜡螟）的幼虫。

蜡虫呈中白色，脚端黑色，细小的头部也是黑色的。在野外的蜡虫会寄生在蜜蜂的蜂巢，主要吃茧、花粉及蜜蜂脱下的皮，也会咬破蜂蜡。所以养蜂业认为它们是害虫。饲养的蜡虫可以长时间不进食，或是被冷藏。一般会在谷类及蜜糖下饲养。

Waxworms are the caterpillar larvae of wax moths, which belong to the snout moth family (Pyralidae). Two closely related species are commercially bred – the lesser wax moth (Achroia grisella) and the greater wax moth (Galleria mellonella). They belong to the tribe Galleriini in the snout moth subfamily Galleriinae. Another species whose larvae share that name is the Indian meal moth (Plodia interpunctella), though this species is not available commercially.