This presentation summarizes the current evidence about the effectiveness of mutual help groups and the mechanisms of action in these groups, including AA, SMART, LifeRing, and WFS. AA is comparably effective to well-implemented CBT. The evidence so far suggests that the other groups are comparably effective to AA. Further studies are in progress. Similar to evidence about common factors in psychotherapy, mutual help groups appear to have common factors. Any freely chosen mutual help group appears likely to be helpful. This presentation also overviews the range of mutual help groups currently available, their surface differences, and interventions for clients who report having no interest in attending any group.