A display device includes a folding area foldable around a virtual folding axis, and a non-folding area adjacent to the folding area, a display panel, and a window disposed on the display panel. The window includes a patterned glass including a patterned part having at least one groove pattern on a top surface of the patterned part, and corresponding to the folding area, and a non-patterned part adjacent to the patterned part and corresponding to the non-folding area, and a filling layer filled in the at least one groove pattern. The filling layer includes a first filling part in contact with the patterned part, and a second filling part in contact with the first filling part.