The present invention relates to a backlight unit having a reflective portion, including a light source module for emitting a light, a first reflective portion arranged spaced a first distance away from one side of the light source module to have an open region, and a second reflective portion arranged spaced a second distance which is greater than the first distance away from the other side of the light source module to have at least a portion with a sloped surface for reflecting the light toward the open region of the first reflective portion.