A programmable gamma circuit for gamma correction is disclosed. The programmable gamma circuit includes a string digital-to-analog converter, a first operational amplifier, and an output resistor string. The string digital-to-analog converter selects an analog voltage from a plurality of candidate voltages according to a digital reference code. An output terminal of the first operational amplifier outputs a first output voltage. A positive input terminal of the first operational amplifier is electrically connected to the string digital-to-analog converter for receiving the analog voltage. The output resistor string is divided into a first resistor part and a second resistor part by a connection terminal which is electrically connected to a negative input terminal of the first operational amplifier, and a resistance of the first resistor part is a multiple of a resistance of the second resistor part.