An organic light emitting diode (OLED) display device including a substrate having a display region and a non-display region surrounding the display region; an OLED on the substrate in the display region; an encapsulation substrate bonded to the substrate via an adhesive layer such that the encapsulation substrate and the substrate face each other; and a step-difference compensation portion in the non-display region and configured to compensate for a step difference between the display region and the non-display region.