A display device includes: a substrate; a display element on the substrate; a capping layer on the display element; an optical layer on the capping layer, and including: a first optical layer on the display element; and a second optical layer on the first optical layer; and a thin film encapsulation layer on the optical layer, and including: a first inorganic encapsulation layer on the second optical layer; an auxiliary layer on the first inorganic encapsulation layer; an organic encapsulation layer on the auxiliary layer; and a second inorganic encapsulation layer on the organic encapsulation layer. A refractive index of the second optical layer is smaller than a refractive index of the capping layer, and a refractive index of the first optical layer is between the refractive index of the second optical layer and the refractive index of the capping layer.