A backlight module includes a frame, a light source, a light guide plate, a wavelength conversion layer, and an optical film group. The light source is disposed in the frame. The light guide plate is disposed in the frame, and the light guide plate includes a light emitting surface, a light incident surface, and at least one side wall. The light source is disposed corresponding to the light incident surface. The side wall connects the light emitting surface and the light incident surface. The wavelength conversion layer is at least disposed on the side wall. The wavelength conversion layer is configured for converting light provided by the light source into white color. The optical film group is disposed on the light emitting surface of the light guide plate.