A gamma tab voltage generator includes a plurality of, a data calculator configured to generate a buffer selection information and a buffer combination information based on a current capacity of buffer, a plurality of digital-to-analog converters configured to generate gamma tab voltages based on a gamma tab voltage information, a buffer selector configured to connect input terminals of the buffers selected based on the buffer selection information to output terminals of the digital-to-analog converters, and a buffer combiner configured to connect output terminals of the selected buffers to one another in response to the buffer combination information.