An exemplary backlight module (2) includes a frame (22) having a plurality of side walls (221), a light guide plate (23) having a light incident surface (231) and a light output surface (233) contained in the frame, at least one optical films (21) disposed adjacent to the light output surface of the light guide plate, and a light source assembly (25) disposed adjacent to the light incident surface of the light guide plate. The frame has at least one elastic fixing clip (225) for fixing the at least one optical films therein. With this configuration, the elastic fixing clip can firmly fix the optical films in the plastic frame. Therefore, the backlight module having the optical films and the plastic frame can be mechanically stable and operate properly.