Quercus buckleyi, commonly known as Texas red oak or Buckley's oak, is a species of flowering plant in the beech family. It is endemic to the southern Great Plains of the United States (Oklahoma and Texas). Quercus buckleyi is smaller and more likely to be multi-trunked than its close relative, the Shumard oak. The two species are interfertile, and hybrids are common along a line from Dallas to San Antonio. Texas red oak usually is 30 to 50 feet (9 to 15 meters) tall at maturity, and seldom reaches a height of more than 75 feet (23 meters).