A new species of Rhinocerotidae, Brachypotherium minor n. sp., from the Early Miocene of Buluk, northern Kenya, is described. The new species shares with other members of the genus large sexually dimorphic incisors, flattened buccal walls on its molars, and a low astragalus, but differs from other species of Brachypotherium Roger, 1904 in its small size, placement of the orbit, having widely separated temporal lines, and more simple molar crown morphology. A comparison of the new species with other brachypotheres suggests that the new species may be present at a small number of other sites, and that the brachypothere group may contain more than one African lineage, adding to our understanding of the diversity of African rhinoceroses.