A display device includes: a display unit including a plurality of pixels to display an image; a first power supply to generate a first power voltage; a second power supply to generate a second power voltage; and a signal controller to control the first power supply to supply the first power voltage to the display unit in response to at least one control signal associated with luminance of the image, and to control the second power supply to stop supplying the second power voltage after the first power voltage starts to be supplied.