A display device includes a light guide plate which includes a light incident surface, a light exiting surface connected to the light incident surface, and an opposite surface facing the light exiting surface, a light source which faces the light incident surface and is configured to emit a light, a reflective sheet which faces the opposite surface and reflects the light, a first pattern which is unitary with the light guide plate and protruded from the opposite surface, a pressure sensitive adhesive which is on an upper surface of the reflective sheet and contacts the first pattern, and a display panel which is configured to receive the light exiting through the light exiting surface and display an image.