Example embodiments relate to a backlight unit and a display apparatus employing the same. The backlight unit may include a light source; a polarization conversion unit configured to convert polarization of light incident from the light source; and a light guide plate configured to emit light incident through the polarization conversion unit. The light guide plate may include a plurality of light emitting portions configured to emit light through specular reflection. The light polarized by the polarization conversion unit may maintain its polarization state when it is subsequently emitted from the light guide plate.