This article describes the effectiveness of interventions aimed at increasing self-efficacy and consequently, changing addiction behaviours. Electronic databases were searched and bibliographies of retrieved references scanned. Ten studies targeting tobacco smoking, alcohol and illicit drug use met the inclusion criteria. The interventions ranged from computer-generated tailored letters to intensive group-based interventions. Seven of the 10 studies reported positive effects of interventions upon self-efficacy. The two that assessed behaviour change reported a significant effect but as neither performed mediation analyses, behaviour change could not reliably be attributed to self-efficacy change. In conclusion, self-efficacy can be increased using a range of methods. There is, however, little evidence to determine whether such increases change behaviour.