Provided are an optical film for improving a contrast ratio, a polarizing plate comprising same, and a liquid crystal display comprising same, the optical film comprising a base layer and a contrast ratio-improving layer formed on the base layer, wherein the contrast ratio-improving layer comprises a first resin layer and a second resin layer directly formed on the first resin layer, wherein the refractive index of the first resin layer is different from that of the second resin layer, wherein the first resin layer comprises: a plurality of embossed first optical patterns formed to be separated in a first direction; a plurality of embossed second optical patterns formed to intersect with the first optical patterns and be separated in a second direction; and dented parts formed by the intersection of the first optical patterns and the second optical patterns, wherein the dented parts have a height lower than that of the first resin layer.