North Brother, also known as Île du Nord, is a round 6 ha coral island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory. It is one of the three islands in the Three Brothers group on the western side of the atoll, and forms part of the Chagos Archipelago strict nature reserve. It has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for 20,000 seabirds, notably Audubon's shearwaters of which 420 pairs were recorded in a 2004 survey.