A backlight unit includes a light source unit having a light source configured to emit a first light, a quantum dot sheet configured to emit a second light having a different color from the first light, a light guide plate configured to guide a light exiting from the light source unit or the quantum dot sheet, and an optical member including a prism sheet and configured to control the light exiting from the light guide plate. The quantum dot sheet includes a polymer resin and a plurality of first and second quantum dots, which are dispersed in the polymer resin. The second light is a white light obtained by mixing a red light, green light, and a blue light, and the second light has a concordance rate with an Adobe RGB color space which is no less than by about 99.9%.