Abstract: A display device includes: a substrate including a folding area and a non-folding area adjacent to the folding area; a plurality of first pixels in the folding area and each having a first light emitting area; a plurality of second pixels in the non-folding area and each having a second light emitting area having a size that is different from a size of the first light emitting area; and a window on the first and second pixels and including a plurality of grooves repeatedly arranged along a first direction in the folding area, and wherein each of the grooves includes a first groove formed from a first surface of the window toward a second surface of the window facing the first surface and a second groove formed from the second surface toward the first surface, and the first groove and the second groove are alternately arranged.