A backlight module including a carrier plate, a plurality of light sources, at least one low reflective portion, and a modulation film is provided. The carrier plate has a carrier surface carrying the light sources while the low reflective portion is disposed on the carrier surface between an outer light source and a side edge of the carrier plate. The reflectance of the low reflective portion is less than that of the carrier surface. The modulation film is disposed above the light sources while the low reflective portion has a projection area on the modulation film. The projection area has a lower normalized transmission ratio comparing to adjacent areas along an extending direction of the side edge of the carrier plate.