Abstract: An easily removable ankle-foot orthosis 11 is formed by molding an inner liner of plastazote foam 24 and an outer layer of polypropylene gel 25 to a positive shaped mold 10 of the foot 12 and lower leg 14. The positive mold includes a pair of opposed protruding longitudinal ribs 18, 20 disposed alongside the lateral and medial surfaces of the lower half of the leg to below the ankle. The resulting orthosis, which comprises an open-toed boot-shaped structure formed having a continuous longitudinal frontal opening 46, is adapted for securely maintaining the foot and leg of a wearer in a slightly less than 90.degree. relationship to one another, the rigidity of the orthosis being enhanced by the longitudinal ribs formed therein. The orthosis is easily removable through use of the frontal opening and may include a plurality of transverse binding straps 50 for snugly fitting a single orthosis to a variety of foot and leg sizes.