Orthotic device for the ankle joint for external fixation of the ankle joint, with a median supporting shell and a lateral supporting shell forming a shell composite by means of a connecting device is provided. The shell composite is provided with a lining for form-fitting contact of the orthotic device for the ankle joint. By the orthotic device for the ankle joint, the joining device has an elastic connecting clasp with a tibial clasp opening which secures the supporting shells in their relative arrangement so that their positions are variable.