A display device includes a window and a display panel coupled to a bottom surface of the window. The display panel has a substantially regular tetragonal shape or a substantially rectangular shape in a plan view, and the window includes a base member and a bezel layer on a bottom surface of the base member. Between one and three light-transmissive main alignment marks and a transmission area having a different shape than that of the display panel are defined in the bezel layer, and each of the main alignment marks is arranged at a position corresponding to a vertex of the display panel or at a position corresponding to a vertex of an imaginary regular tetragon or of an imaginary rectangle that has the same center point as the display panel and that is larger than the display panel.