A backlight module includes a light guide plate, a light source, an optical film set and at least one light shielding layer. The light guide plate has a light incident surface and a light emitting surface adjacent to the light incident surface. The light source is disposed beside the light incident surface. The optical film set includes a first surface, a second surface and at least one end surface. The first surface and the second surface are opposite to each other. The at least one end surface is connected to the first surface and the second surface. The optical film set is disposed on the light emitting surface of the light guide plate. The first surface faces the light emitting surface. The at least one light shielding layer is disposed on the at least one end surface. A display device using the backlight module is also provided.