A source driver includes a buffer unit including a plurality of unit buffers corresponding to a plurality of source lines, where each of the plurality of unit buffers includes a plurality of input terminals and an output terminal connected to at least one of the plurality of source lines, and a decoder unit configured to receive image data and a plurality of gamma voltages, and input at least one of the plurality of gamma voltages to the plurality of input terminals of each of the plurality of unit buffers, using the image data. The decoder unit inputs two or more of the gamma voltages, having different magnitudes, to the plurality of input terminals of each of first unit buffers among the plurality of unit buffers, and the first unit buffers output a gradation voltage higher than a first voltage and lower than a second voltage.