An optical sheet and a liquid crystal display including the same are disclosed. The optical sheet includes a reflective polarizing film, a first adhesive layer on one surface of the reflective polarizing film, and a first diffusion layer on the first adhesive layer. The first adhesive layer has first and second thicknesses. The first diffusion layer includes a first light transmitting material and a plurality of first diffusion particles. At least one of the first diffusion particles has a portion protruding above a surface of the first light transmitting material, and a height of the portion, h1, substantially satisfies the following equation: 0.1D1≦h1≦0.7D1, where D1 is a diameter of the at least one of the first diffusion particles. The first thickness, T1, and the second thickness, T2, substantially satisfy the following equation: 10 nm≦|T1−T2|≦2 μm.