This invention relates to an improved hair styling device, and provides a hair styling device for imparting a wave to a tress of hair. The device comprises a tube (110) having a longitudinal axis, the tube being open at at least one of its longitudinal ends whereby the tress of hair can be introduced into the tube. The tube is longitudinally extendable between a non-extended condition and an extended condition. The inside of the tube has at least one barrier (120) which can engage the tress of hair as the tube moves towards its non-extended condition, the barrier controlling the deformation of the tress of hair and thereby controlling the form of the wave produced in the tress of hair.