A foldable display device includes a flexible display panel, a case supporting the flexible display panel, a bonding member fixing the flexible display panel to the case. The case includes a hinge portion, and supports respectively coupled to the hinge portion at opposing sides of the hinge portion. The flexible display panel includes a bendable area corresponding to the hinge portion, and planar areas respectively at opposing sides of the bendable area and corresponding to the supports of the case. The bonding member is between a support of the case and the corresponding planar area of the flexible display panel, and is displaceable with respect to the support along one of a thickness direction and a width direction of the flexible display panel when the flexible display panel is folded.