Quercus sinuata is a North American species of oak comprising two distinct varieties, Quercus sinuata var. sinuata and Quercus sinuata var. breviloba. Morphologically intermediate forms may occur where range overlap brings the two taxa together. Quercus sinuata var. breviloba is native to central and north central Texas, south central and southwest Oklahoma, and to Coahuila, Nuevo León, and Tamaulipas in northern Mexico. Quercus sinuata var. sinuata is native to the south-central and southeastern United States from central Texas and southwestern Arkansas to the Carolinas. Their respective ranges intersect in the Hill Country of central Texas, where streams flowing through dry, brushy limestone hills create a mosaic of wet and well drained habitats.