A snap-fit for fixing optical films is disclosed. The optical film includes at least one ear hook arranged above a border of a plastic frame. The plastic frame is assembled with a back frame so as to fix a light guiding plate within the back frame. The snap-fit includes a press portion and a connection portion extending from a first side of the press portion. The connection portion and the press portion cooperatively form an angle with a predetermined degree. The press portion presses the ear hook of the optical films on the border of the plastic frame. The connection portion clasps with the hook of the sidewall. By adopting the snap-fit, not only the narrow bezel design can be achieved, but also the optical film can be stably fixed. A backlight module with the above snap-fit and the liquid crystal display are also disclosed.