A backlight module includes a plurality of first light sources emitting first light and a light guide plate. The first light sources are arranged in a line and spaced from each other. Two adjacent first light sources define a first space therebetween. The light guide plate includes a first light incident surface and a light output surface. The first light incident surface has a plurality of bright areas respectively corresponding to the first light sources and a plurality of dark areas respectively corresponding to the first spaces. A plurality of first reflectors is disposed on the plurality of dark areas of the first incident surface. The light output surface is adjacent and perpendicular to the light incident surface.