Narrative reviews conclude that behavioral couples therapy (BCT) produces better outcomes than individual-based treatment for alcoholism and drug abuse problems (e.g., [Epstein, E. E., & McCrady, B. S. (1998). Behavioral couples treatment of alcohol and drug use disorders: Current status and innovations. Clinical Psychology Review, 18(6), 689-711; O'Farrell, T. J., & Fals-Stewart, W. (2003). Alcohol abuse. Journal of Marital and Family Therapy, 29(1), 121-146]). However, the strength and consistency of this effect favoring BCT has not been examined because a meta-analysis of BCT studies has not been reported. This meta-analysis combines multiple well controlled studies to help clarify the overall impact of BCT in the treatment of substance use disorders. A comprehensive literature search produced 12 randomized controlled trials (n=754) that were included in the final analyses. There was a clear overall advantage of including BCT compared to individual-based treatments (Cohen's d=0.54). This was true across outcome domains (frequency of use d=0.36, consequences of use d=0.52, and relationship satisfaction d=0.57). However the pattern of results varied as a function of time. BCT was superior to control conditions only in relationship satisfaction at posttreatment (d=0.64). However, at follow-up BCT was superior on all three outcome domains (frequency of use d=0.45, consequences of use d=0.50, and relationship satisfaction d=0.51). In addition to other control conditions, BCT also outperformed individual cognitive behavioral therapy without couples therapy (d=0.42). Larger sample sizes were associated with higher effect sizes (p=0.02). However, treatment dose and publication year were not related to effect size. Overall, BCT shows better outcomes than more typical individual-based treatment for married or cohabiting individuals who seek help for alcohol dependence or drug dependence problems. The benefit for BCT with low severity problem drinkers has received little attention and one study suggests its efficacy may not extend to this subgroup.