A display device including a backlight unit and a display panel disposed on the backlight unit. The backlight unit includes a light guide plate, a wavelength conversion layer, and a cover member. The light source unit is disposed adjacent to a surface of the light guide plate. The wavelength conversion layer is disposed between the light source unit and the light guide plate, and contacts the surface of the light guide plate. The cover member is disposed between the light source unit and the light guide plate, and seals the wavelength conversion layer.