The Cameroon sunbird is a species of bird in the family Nectariniidae. It is native to montane forests of Cameroon, Nigeria, and Equatorial Guinea, including the island of Bioko. It inhabits high-altitude forests and feeds primarily on nectar and insects. The species shows marked sexual dimorphism, with males displaying a metallic blue breast and duller females, and is known to make seasonal altitudinal movements. The species is classified as Least Concern by the International Union for Conservation of Nature (IUCN), although its population trend is decreasing due to habitat loss.