A backlight unit includes a light source that emits light and a light guide plate disposed adjacent to the light source. The light guide plate includes an incident surface to which light is incident, an exit surface from which light incident through the incident surface exits, a reflection surface facing the exit surface to reflect the incident light, and a plurality of lenticular protrusions disposed on the exit surface. The reflection surface includes an inclined surface proximal to the incident surface and inclined with respect to the exit surface.