Optical films, and organic-light-emitting display apparatuses, include a high refractive index pattern layer including a first surface and a second surface facing each other. The first surface includes a pattern having grooves. The grooves each have a curved surface and a depth greater than a width. The high refractive index pattern layer is formed of a material having a refractive index greater than 1. Further included is a low refractive index pattern layer formed of a material having a refractive index smaller than that of the material constituting the high refractive index pattern layer. The low refractive index pattern layer includes a filling material for filling grooves. A tilt angle, θ, of each groove satisfies the following condition, 15°≦θ≦75°.