Bucephala is a genus of diving ducks found in the Northern Hemisphere. The genus name is derived from Ancient Greek boukephalos, "bullheaded", from bous "bull", and kephale, "head", a reference to the crest of the bufflehead making its head look large.
The bufflehead was formerly treated as the only member of the genus (sometimes unnecessarily changed to Charitonetta) while the goldeneyes were incorrectly placed in Clangula (as Clangula americana), the genus of the long-tailed duck, which at that time was placed in Harelda. It may yet be correct to recognise two genera, as the bufflehead and the two goldeneyes are well diverged. In this case, Bucephala would be restricted to B. albeola and the name Glaucionetta (Stejneger, 1885) resurrected for the goldeneyes.