The eastern double-collared sunbird (Cinnyris mediocris) is a species of bird in the family Nectariniidae. It is found in upland areas of Kenya and northern Tanzania. The eastern double-collared sunbird is a small species. The adult male has upper parts a metallic green, dark wings and tail, and a red breast band and olive belly. The beak is strongly curved and used to sip nectar from flowers. The adult female is olive above, with brown on the wings and yellowish-green underparts. The eastern double-collared sunbird is native to mountainous regions of Kenya and northern Tanzania. It is found in forests, upland pasture, heathland and bamboo. It descends to lower altitudes after the breeding season.