There are provided a display device and a method of compensating for degradation thereof. The display device includes a display panel including pixels, a sensing unit configured to measure threshold voltages of the pixels, respectively, and a timing controller configured to determine grayscale compensation values with respect to the pixels corresponding to the threshold voltages, respectively, and to compensate input image data with respect to the pixels based on the grayscale compensation values, respectively, wherein the grayscale compensation values have a linear relationship with a grayscale of the input image data by using a linear slope value determined based on the threshold voltages.