A display device with low power consumption is provided. A display device having high visibility regardless of the ambient brightness is provided. The display device includes a light-receiving element, a display element, a first transistor, and a second transistor. One of a source and a drain of the first transistor is electrically connected to one electrode of the light-receiving element. The one of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the second transistor. The display device has a function of, by turning on the second transistor, changing the gray level of the display element in accordance with the amount of light detected by the light-receiving element.