A display device includes a display panel, a gate driver, a data driver, and a driving control unit. The display panel includes pixels connected to a corresponding one of gate lines and a corresponding one of data lines. The gate driver drives the gate lines. The data driver includes first pads and second pads. The first pads are connected to each of first data lines of the data lines, and the second pads are connected to each of second data lines of the data lines. The driving control unit provides control signals and a data signal to the data driver, and to control the gate driver. The data driver includes a digital-to-analog converter and a switching circuit. The digital-to-analog converter converts the data signal into analog signals. The switching circuit sequentially outputs the analog signals to the first pads during a test mode.