An extendable stirrup has a main stirrup and a retractable step parallel to and slideably attached to the main stirrup. The retractable step has an upper lift portion and a lower step portion. A latch holds the retractable step in the retracted position for riding. For mounting, the user releases the latch thereby allowing the retractable step to automatically descend to an extended position. The user places a foot on the lower step portion of the retractable step to assist in mounting a saddled animal. After mounting the saddled animal, the user engages the upper lift portion with his boot and raises the retractable step to a retracted position whereby the latch holds the retractable step in the retracted position adjacent to the main stirrup.