A foldable display device includes a first display panel which displays a portion of an image; a second display panel which displays a second portion different from the first portion of the image; a first protecting window on the first display panel; a second protecting window on the second display panel; and a flexible material layer between the first and second protecting windows. Side surfaces of the first and second protecting windows which contact the flexible material layer, respectively, are inclined with respect to a surface of each of the first and second protecting windows.
