A foldable coat hanger, which is constructed to be easily folded and unfolded as desired, so that the volume thereof can be reduced as desired and the space-related problem occurring in the use of the conventional hangers can be solved. Further, the size of the coat hanger can be stepwisely adjusted between a plurality of size stages, so that the size of the coat hanger can be appropriately adjusted according to the size of a garment, thus efficiently fitting garments having different sizes and efficiently hanging and protecting the garments.