Abstract: Securely stacking and height adjustable bar stools are provided. In one embodiment of the present invention, the seat of a bar stool includes an upper leg restraining system that accommodates a pair of legs from another bar stool that is to be securely stacked on top. In conjunction with the upper leg restraining system, a leg bracing system is provided to accommodate and restrain the pair of legs from another bar stool. In addition, the seat height of a bar stool may be incrementally increased by attaching a plurality of leg extenders to previously added leg extenders until a desired bar stool seat height has been attained.