The invention provides an optical film assembly, a backlight module, and a display device. The backlight module includes a light source emitting at least a first light, a first optical film, and a second optical film laminated to the first optical film, wherein the first optical film includes a functional layer but does not include a base film, the functional layer is a diffusion film, a brightness enhancement film, a reflection film, or a prism film, and the second optical film is a light conversion layer, the light conversion layer receives the first light and converts the first light to at least a second light to emit, such that a light emission angle of the backlight module matches a requirement of wide viewing angle. The invention could broaden the light emitting angle of the backlight module to make the display device with the backlight module achieve wide viewing angle.