A timing controller utilized in a display device includes an image processing circuit, a luminance adjusting circuit, a data converting circuit and a driving signal generating circuit. The image processing circuit performs image processing on image data of an image signal. The luminance adjusting circuit adjusts luminance of the processed image data according to a luminance characteristic of the display panel of the display device. According to a pixel arrangement of the display panel, the data converting circuit converts the adjusted image data to display data provided to a driving circuit of the display panel. The driving signal generating circuit generates a driving signal to control the driving circuit according to a synchronous signal of the image signal.