Pennant's colobus or Pennant's red colobus is a species of tree-dwelling primate in the family Cercopithecidae. It is endemic to tropical Central Africa. Three subspecies have traditionally been recognised but its distribution is peculiarly disjunct and has been considered a biogeographical puzzle, with one population on the island of Bioko, a second in the Niger River Delta in southern Nigeria, and a third in east-central Republic of Congo. It is found in rainforests and marshy forests. It is threatened by habitat loss and hunting for bushmeat.

Thomas Pennant was a Welsh naturalist, traveller, writer and antiquarian. He was born and lived his whole life at his family estate, Downing Hall near Whitford, Flintshire, in Wales.