A display device includes a display panel including a plurality of pixels for displaying an image, and a panel controller configured to receive image signals and convert the image signals into correction image signals. The panel controller includes a first circuit to accumulate the correction image signals each frame period and generate degradation data based on the accumulated correction image signals, and a second circuit configured to determine reference data from the degradation data and generate the correction image signals by correcting the image signals to have a target luminance that is changed based on the reference data.