A display device includes a display panel, a timing controller, a data driver, and a light source unit. The display panel includes a plurality of data lines. The timing controller receives a control signal and image data, and outputs a data control signal, converted image data, and a mode selection signal. The data driver receives the data control signal, the converted image data, and the mode selection signal from the timing controller, outputs a data voltage to the plurality of data lines, and operates in a first mode which is a power saving mode or a second mode which is a normal driving mode in response to the mode selection signal. The light source unit includes a light source part that operates in association with a source driving circuit included in the data driver.