A source driver including a decoder configured to receive image data and an activation signal, determine a target voltage based on the image data, and select at least one gamma line for generating the target voltage from among a plurality of gamma lines, which are configured to transmit different gamma voltages, respectively, and a buffer circuit including a plurality of input terminals and configured to be connected to the selected at least one gamma line and generate an output voltage based on at least one gamma voltage obtained from the selected at least one gamma line may be provided. The decoder may be further configured to select a gamma line group including the selected at least one gamma line to be connected to the plurality of input terminals of the buffer circuit during a slew period of the buffer circuit in accordance with the activation signal.