Amoebidium is a genus of unicellular, symbiotic eukaryotes in the Opisthokont group Mesomycetozoea, family Amoebidiidae. Amoebidium species attach to the exoskeleton of freshwater aquatic arthropods such as midge larvae and water fleas (Daphnia). The type species is Amoebidium parasiticum, which is also one of the only species to be cultured axenically.