A foldable display device includes a flexible display module, a case, first and second support plates, and a first protective film. The flexible display module includes a display surface and a back surface opposing the display surface. The case is on the back surface and includes: a hinge portion, and first and second covers rotatably coupled to the hinge portion in first and second directions, respectively. The second direction is opposite the first direction. The first support plate is between the flexible display module and the first cover, and supports a first side portion of the flexible display module. The second support plate is between the flexible display module and the second cover, and supports a second side portion of the flexible display module. The first protective film is coupled between the first and second support plates, and covers the back surface exposed between the first and second support plates.