A luminance control unit includes: a driving power voltage setting unit configured to determine a driving power voltage to be provided to a display panel, the driving power voltage corresponding to a target brightness, based on a plurality of driving power voltages respectively corresponding to a plurality of reference brightnesses of the display panel; and a gamma voltage setting unit configured to determine a target luminance corresponding to the target brightness, based on a plurality of target luminances respectively corresponding to the plurality of reference brightnesses, and to set gamma voltages for implementing the target luminance, wherein the driving power voltage and the gamma voltages are differently set with respect to the same reference brightness according to an ambient illumination intensity of the display panel.