A display device including a display panel including a planar portion and a curved portion extending from the planar portion, a controller to provide a data signal representing an image to be displayed on the planar portion and the curved portion to the display panel, in which the controller is configured to provide a data signal representing an image that is reduced at a greater extent to a portion of the curved portion that is disposed further away from the planar portion, and the display device is a head-mounted display device.