A display device includes a lower substrate, a sub-pixel structure, an optical filter layer, a color filter layer, an upper substrate, and an alignment structure. The lower substrate has a display area and a peripheral area surrounding the display area. The sub-pixel structure is disposed in the display area on the lower substrate. The optical filter layer is disposed on the sub-pixel structure. The color filter layer is disposed on the optical filter layer. The upper substrate is disposed on the color filter layer. The alignment structure is disposed in the peripheral area on a bottom surface of the upper substrate, and contains a material equal to a material forming the optical filter layer and the color filter layer.