A display device includes: a substrate; a color filter layer disposed below the substrate; a color control layer disposed below the color filter layer; and an optical auxiliary layer disposed between the substrate and the color filter layer and having a base portion and a plurality of recess portions, the plurality of recess portion defined in the base portion and recessed in a direction toward the substrate, wherein an average refractive index of the optical auxiliary layer is greater than or equal to an average refractive index of the substrate and is less than or equal to an average refractive index of the color filter layer.