An ankle-foot orthotic which permits plantarflexion and dorsiflexion while restricting inversion and eversion of the ankle. The orthotic includes a lower leg shell attachable to the lower leg of the wearer inside of the wearers trousers, a foot shell held in place inside the wearer's shoe, by the shoe itself, and a pair of mechanical joints attaching the lower leg shell to the foot shell. The mechanical joints are pivotally attached to the foot shell allowing rotation on an axis through the ankle joint, but are rigid perpendicular to the axis of the ankle joint thereby restricting sideways bending movement of the ankle. The mechanical joints have internal springs which allow translational movement of the lower leg shell relative to the foot shell providing greater comfort to the wearer by reducing rubbing and chafing of the user's leg while creating extra cushioning and shock absorption.