The present article aims at answering the question whether an early or late treatment approach is the ideal period for Herbst therapy. This topic will be discussed by summarizing and evaluating the short- and long-term effects of the Herbst appliance on the dentofacial complex. Special emphasis will be given to the treatment outcome in relation to the patient's somatic and skeletal maturity at the time of therapy. Furthermore, the long-term stability of the treatment results will be addressed. The available knowledge in the literature demonstrates that the ideal period for Herbst treatment is in the permanent dentition at or just after the peak of pubertal growth corresponding to the skeletal maturity stages FG to H of the middle phalanx of the third finger (implying the pre-capping to pre-union stages of the ephiphysis and metaphysis). As mandibular growth stimulation is also possible in postadolescent young adult subjects a new concept of Class II therapy is presented in which the Herbst appliance is used as an alternative to orthognathic surgery in older Class II subjects.