A flexible display device according to an embodiment includes a display member, a window member on the display member and having a rear surface facing the display member and a top surface located opposite to the rear surface, a thin-film layer including a base layer having a first surface contacting the rear surface and a second surface located opposite to the first surface and a plurality of particles coupled to the second surface, a protection member spaced apart from the window member, the display member being between the protection member and the window member, a first adhesion member configured to couple the thin-film layer to the display member, and a second adhesion member configured to couple the display member to the protection member. Each of the particles protrudes from the second surface of the base layer to the protection member.