An organic light emitting diode display device for changing a gamma reference voltage step by step in accordance with an image brightness of a current frame to reduce damage with which the organic light emitting diode and the driving transistor thereof are applied is disclosed. In the organic light emitting diode display device, a brightness detector calculates a maximum brightness value of each pixel using inputted image data of current frame. An adder adds all maximum brightness values of each pixel which are detected by the brightness detector. An average value calculator calculates an average brightness value of a current frame using an added value of maximum brightness values which are added by the adder. A gamma weight calculator calculates a gamma reference voltage weight which is set to correspond to the calculated average brightness value among predetermined gamma reference voltage weights. And a gamma reference voltage generator changes a gamma reference voltage step by step in accordance with a gamma reference voltage weight which is calculated by the gamma weight calculator.