Oecomys concolor, also known as the Unicolored Oecomys, Unicolored Rice Rat, or Unicolored Arboreal Rice Rat, is a species of rodent in the genus Oecomys of family Cricetidae. It is found in tropical rainforest in Amazonia, but its range is poorly documented; it has been recorded in northwestern Brazil, southeastern Colombia, and southern Venezuela.