A display device includes a light guide plate, at least one illuminating element, a side frame, and a display panel. The light guide plate includes a main body and at least one light-incident protrusion part. The main body has a light-emitting surface. The light-incident protrusion part is connected to the main body and has a light-incident surface. The illuminating element is arranged along the light-incident surface and is capable of emitting a light beam. The light beam enters the light guide plate from the light-incident surface and leaves the light guide plate from the light-emitting surface. The side frame is located on the light guide plate. The display panel is located between the light guide plate and the side frame. The side frame and the display panel expose the light-incident protrusion part. The side frame of the display device described herein has the small width.