A display device includes: a display panel including a plurality of pixels; a power supply configured to generate a gamma power voltage based on a power control signal; a gamma voltage generator configured to generate gamma voltages based on the gamma power voltage and a gamma control signal; a data driver configured to generate a data signal corresponding to a grayscale value included in image data using the gamma voltages and to provide the data signal to the pixels; and a power controller configured to adjust the power control signal and the gamma control signal based on a maximum voltage level of the data signal, wherein a voltage level of the gamma power voltage is proportional to the maximum voltage level of the data signal.