Abstract: An ankle orthosis device is described which comprises a foot receiving cup or shoe which is integrated with or to which is rigidly attached a force transmitting rib which has an inverted Y-shape. At the proximal end of the Y is slidably attached to the rib for securing the device to the lower leg near the distal end of the tibia. Inversion or eversion torque producing forces applied to the device are transmitted through the cup or shoe and rib to the tibia so that there is no tendency to produce injury causing inversion or eversion of the ankle as a result of the torque. Generally free movement in dorsiflexion and plantar flexion is permitted by the device, which allows it to be used for walking, running, sports events and the like, as well as being useful in a postoperative or other therapeutic ankle treatment program. The device can be in the form of shoe inserts, attached to the heel of a shoe or incorporated into the body of a shoe.