The bufflehead is a small sea duck of the genus Bucephala, the goldeneyes. This species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Anas albeola.

The sea ducks (Mergini) are a tribe of the duck subfamily of birds, the Anatinae. The taxonomy of this group is incomplete. Some authorities separate the group as a subfamily, while others remove some genera. Most species within the group spend their winters near coastal waters. Many species have developed specialized salt glands to allow them to tolerate salt water, but these are poorly developed in juveniles. Some of the species prefer riverine habitats. All but two of the 22 species in this group live in far northern latitudes.