Abstract: Spirituality and religion are frequently acknowledged as significant contributors to individuals’ recovery from substance use disorders. This review focuses on the role that spirituality or religion plays in substance abuse treatment outcomes. Our search of three databases—PubMed, CINAHL, and Psych Info—turned up 29 eligible studies for review. We group our findings according to whether the study’s focus was on alcohol only or alcohol and other drug use. The most common treatment outcome was abstinence followed by treatment retention, alcohol or drug use severity, and discharge status. For most studies, we found evidence suggesting at least some support for a beneficial relationship between spirituality or religion and recovery from substance use disorders. Our review addresses the strengths and limitations of these studies.