A backlight unit includes a substrate comprising a first area having light source blocks and a second area having light source blocks, and a light source driver disposed on at least one side of the substrate and electrically connected to the light source blocks of each of the first and second areas through each of first and second sensing lines. The first sensing lines electrically connected to the light source blocks of the first area have a first resistance value, and the second sensing lines electrically connected to the light source blocks of the second area have a second resistance value.