A data driver includes a gamma voltage generator configured to generate gamma voltages based on a number of data bits of a pixel data; a first digital-to-analog block configured to generate a plurality of time-division gamma voltage signals respectively corresponding to a plurality of gamma voltage groups; a plurality of time-division gamma voltage line groups for transferring the plurality of time-division gamma voltage signals; a second digital-to-analog block configured to select a time-division gamma voltage signal among the time-division gamma voltage signals according to upper bits of the pixel data in each channel; a time-division gamma voltage select block configured to select a gamma voltage according to lower bits of the pixel data in each channel; and an output buffer block configured to output the selected gamma voltage in each channel.