A backlight unit is provided. The backlight unit may include a light emitting device package, a light guide plate including a first region and a second region extending from the first region, with upper surfaces of the first and second regions being spaced apart so as to form a stepped surface. A recess may be formed in a lateral surface of the second region to receive the light emitting device package, and an optical sheet may be received on the upper surface of the second region of the light guide plate.