A backlight unit includes a light source unit which has a curved shape, a light guide plate including a curved light incident surface on which light emitted from the light source unit is incident, and a light source cover which has a curved shape corresponding to the curved light incident surface and is configured to surround one side of the light guide plate to dispose the light source unit and the light incident surface inside thereof. A groove is defined in the light source cover and extends toward the inside of the light source cover from an edge portion thereof.