An optical film includes a transparent film having a thickness of 10 to 150 μm and a first layer on a first surface of the transparent film. The first layer has an average in-plane refractive index that is highest of average refractive indices of the transparent film and a layer disposed on the first surface, and the average in-plane refractive index of the first layer is higher than average refractive indices of the transparent film and the layer other than the first layer disposed on the first surface by 0.02 or more, wherein the average in-plane refractive index of the first layer is higher than the average refractive index of the transparent film by 0.02 or more, provided that the layer disposed on the first surface is the first layer alone, and the first layer has an optical thickness D satisfying: 260×N−190−65 nm≦D≦260×N−190+65 nm (N is an integer of 6 to 12).