A display device has a backlight unit and a display panel on the backlight unit. The backlight unit has a bottom cover, a light guide plate on the bottom cover, a reflective sheet under the light guide plate, a printed circuit board disposed at one lateral side of the light guide plate, a plurality of light emitting diodes mounted on the printed circuit board, and two or more optical sheets including a wavelength conversion sheet, wherein the wavelength conversion sheet has a lower substrate, an upper substrate on the lower substrate, a wavelength conversion layer between the lower substrate and the upper substrate, a lower anti-reflective layer under the wavelength conversion layer, a lower impact absorbing layer under the lower substrate, and an upper impact absorbing layer on the upper substrate.