The Rio Branco antbird (Cercomacra carbonaria) is a bird species in the family Thamnophilidae. It is found in Brazil (Roraima) and Guyana. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist shrubland. It is severely threatened by habitat loss. The Rio Branco antbird was described by the English ornithologists Philip Sclater and Osbert Salvin in 1873 and given its current binomial name Cercomacra carbonaria.