A display driver includes a gamma voltage generation unit, a decoder, and a plurality of source amplifiers. The gamma voltage generation unit generates gamma reference voltages. The decoder transforms pixel data corresponding to received image information into data voltages using the gamma reference voltages. The plurality of source amplifiers outputs the data voltages to a display panel. The gamma voltage generation unit includes a first amplifier receiving a reference voltage and a voltage divider including a plurality of resistors and at least one first switch. The at least one first switch turns on or turns off a first connection between an output node of the first amplifier and the plurality of resistors depending on an operation mode. The voltage divider generates at least one first gamma reference voltage among the gamma reference voltages based on an output voltage of the first amplifier.