The Bioko drill is a subspecies of the drill, an Old World monkey. It is endemic to Bioko Island, Equatorial Guinea, located off the west coast of Africa. The drill is one of the largest monkey species, and is considered endangered. The Bioko drill was separated from their mainland counterpart, due to rising sea levels after the end of the last ice age, around 10,000 years ago. The capital of Equatorial Guinea, Malabo, is on Bioko Island. The Malabo market is the primary point of sale for bushmeat on Bioko Island. The drill plays an important role in the cultural tradition of bushmeat consumption, and is locally considered to be tasty, and in some regions, a delicacy. The commercialisation of hunting on Bioko Island has made this practice unsustainable. Hunting of the Bioko drill is banned in most areas of Bioko Island, as they predominantly inhabit protected areas on the island. However, the ban is considered ineffective; hunting remains the largest threat to the drill's population.

The drill is a primate of the family Cercopithecidae, related to baboons and even more closely to mandrills.