A display device includes a folding area foldable about a folding axis and a non-folding area proximate to the folding area. The display device includes a display module that displays an image and a glass window that is disposed over the display module that includes a patterned glass. The patterned glass includes a pattern portion including a groove pattern provided on one surface of the patterned glass to correspond to the folding area and a non-pattern portion disposed adjacent to the pattern portion to correspond to the folding area. The pattern portion has a thickness that is smaller than or equal to one-half a thickness of the non-pattern portion.