This paper reviews methodologically rigorous studies examining group treatments for interview-diagnosed drug use disorders. A total of 50 studies reporting on the efficacy of group drug use disorder treatments for adults met inclusion criteria. Studies examining group treatment for cocaine, methamphetamine, marijuana, opioid, mixed substance, and substance use disorder with co-occurring psychiatric conditions are discussed. The current review showed that cognitive behavioral therapy (CBT) group therapy and contingency management (CM) groups appear to be more effective at reducing cocaine use than treatment as usual (TAU) groups. CM also appeared to be effective at reducing methamphetamine use relative to standard group treatment. Relapse prevention support groups, motivational interviewing, and social support groups were all effective at reducing marijuana use relative to a delayed treatment control. Group therapy or group CBT plus pharmacotherapy are more effective at decreasing opioid use than pharmacotherapy alone. An HIV harm reduction program has also been shown to be effective for reducing illicit opioid use. Effective treatments for mixed substance use disorder include group CBT, CM, and women’s recovery group. Behavioral skills group, group behavioral therapy plus CM, Seeking Safety, Dialectical behavior therapy groups, and CM were more effective at decreasing substance use and psychiatric symptoms relative to TAU, but group psychoeducation and group CBT were not. Given how often group formats are utilized to treat drug use disorders, the present review underscores the need to understand the extent to which evidence-based group therapies for drug use disorders are applied in treatment settings.