Disclosed is a light guide plate for use in a backlight module. The light guide plate includes a light incidence surface, a light exit surface, and a bottom surface opposite to the light exit surface. The light incidence surface is connected between the bottom surface and the light exit surface. The light guide plate has an interior in which an internal chamber is formed and includes two opposite sidewalls and an end wall that is connected between the two sidewalls and is substantially parallel to and spaced from the light incidence surface. The internal chamber include a light source provided at a connection site between the end wall and each of the two sidewalls, whereby light that enters through the light incidence surface and light emitting from the two light sources are subjected to refraction and/or reflection within the internal chamber and then project outward through the light exit surface.