Woven textiles from Çatalhöyük in southern Anatolia are among the earliest-known examples of weaving in the Near East and Europe. Studies of material excavated in the 1960s identified the fibres as flax. New scanning electron microscope analysis, however, shows these fibres—and others from more recent excavations at the site—to be made from locally sourced oak bast. This result is consistent with the near absence of flax seeds at Çatalhöyük, and suggests there was no need for the importation of fibres from elsewhere; it also questions the date at which domesticated flax was first used for fibres. These findings shed new light on early textile production in the Neolithic, suggesting that tree bast played a more significant role than previously recognised.