A backlight unit which includes a light guiding layer having an incident surface on which light is incident and an exit surface from which light is emitted, a light source disposed on the incident surface of the light guiding layer and configured to generate the light, a low refraction layer disposed on the exit surface of the light guiding layer, a color control layer disposed on the low refraction layer, and a protection layer disposed on the color control layer. The protection layer includes a resin composition including a first repeating unit represented by Formula 1: