Display device includes a scan driver to receive a scan start signal and to supply scan signals of a turn-on level to scan lines in response to the scan start signal; a data driver to receive grayscale values and to supply data voltages corresponding to the grayscale values and a reference data voltage to data lines; pixels connected to the scan lines and the data lines, the pixels including display target pixels configured to receive the data voltages and at least one sensing target pixel configured to receive the reference data voltage; and a scan start signal adjusting unit to detect the display target pixels among the pixels using the grayscale values and to adjust a phase of the scan start signal when at least one of the display target pixels comprises a sensing target pixel.