A display device is provided which includes a display panel including a plurality of pixels; a gate driving unit configured to drive gate lines; a data driver configured to drive data lines; and a timing controller configured to generate a plurality of control signals for controlling the gate driving unit and the data driver. The timing controller converts the data signals into an image data signal, a horizontal synchronization signal, a vertical synchronization signal, and a data enable signal, a pulse width of each of the horizontal and vertical synchronization signals corresponding to an aspect ratio of the data signals or a size of a black image display area. The timing controller generates the plurality of control signals according to the image data signal, the data enable signal, and pulse widths of the horizontal synchronization signal and the vertical synchronization signal.