Of particular interest in the psychosocial treatment of addictions is determining how much therapy is required to bring about behaviour change. Stepped care approaches, where non-responders to a less intensive therapy receive a more intensive intervention, aim to only provide intensive assistance to those who need it, thereby allocating therapeutic resources more efficiently. This paper provides a systematic review of stepped care models involving different levels of psychosocial intervention for the treatment of alcohol use disorders and smoking cessation. Five publications on alcohol and three on smoking were included in the review. Due to the heterogeneity of outcome measures, participant characteristics and interventions, a narrative review format was employed. Overall, little evidence was found to suggest that stepping up non-responders to more intensive therapy improved outcomes, a finding that could partially be attributed to a lack of power to find significant effects. In one study, the application of a stepped care approach was found to reduce treatment costs compared with usual care. There was some evidence that the greater differentiation between the intensity of the interventions offered at each step, the better the outcome. Further research is needed to evaluate the efficacy of stepped care approaches to providing psychosocial treatment, employing larger samples and/or consistent definitions of the nature of the interventions offered at each step, and assessing treatment response in a timely manner.