Optical films, and organic light-emitting display apparatuses employing the same, include a high refractive index pattern layer including a first surface and a second surface facing each other, wherein the first surface includes a pattern having a plurality of grooves. The plurality of grooves each have a curved surface and a depth greater than a width thereof. The high refractive index pattern layer is formed of a material having a refractive index greater than 1. The optical films, and the organic light-emitting display apparatuses, further include a low refractive index pattern layer formed of a material having a refractive index smaller than the refractive index of the material constituting the high refractive index pattern layer. The low refractive index pattern layer includes a filling material for filling the plurality of grooves.