Hamadryas is a nymph, the mother of the hamadryads in Greek mythology, and the name has been used repeatedly in scientific naming and may refer to:
Genera Hamadryas (butterfly), a genus of brush-footed butterflies Hamadryas (plant), a genus of plants
Species epithet The hamadryas baboon, Papio hamadryas
Rejected scientific names As a proposed (but rejected) generic name for the king cobra, a snake As a junior synonym generic name for the Tellervini, milkweed butterflies As a junior synonym generic name for the owl butterfly, genus Caligo, a group of butterflies with large spots As a junior synonym generic name for a proposed monotypic genus for Euclemensia woodiella, a rare British moth As a junior synonym species epithet for the lung breathing snail Bulimus eurystomus