A method for manufacturing a display device includes providing a first display device assembly comprising a display module, a first window disposed on the display module, a first window adhesive layer disposed between the display module and the first window, and a first protective layer disposed on the first window. The first protective layer is removed. The first window is removed by providing an acid solution on the first display device assembly. A second window is provided that is disposed on the display module after the first window is removed. A second protective layer is provided that is disposed on the second window after the first protective layer is removed.