A backlight unit is discussed, which includes a frame including a bottom and a sidewall extending from the bottom; at least one substrate located on the frame, and a plurality of light sources mounted on the at least one substrate; and a reflecting sheet located on the at least one substrate, wherein the reflecting sheet includes: a first sheet part located on the bottom, the first sheet part including a plurality of holes corresponding to the plurality of the light sources, and a plurality of first dots; and a second sheet part extended from the first sheet, the second sheet part including a plurality of second dots, wherein the plurality of first dots are positioned adjacent to at least one of the plurality of holes.