Objectives: This review evaluates the evidence on the effects of cognitive-behavioral therapy (CBT) on drug use reduction for young people in treatment for nonopioid drug use. Method: We followed Campbell Collaboration guidelines to conduct a systematic review of randomized and nonrandomized trials. Meta-analytic methods were used to quantitatively synthesize study results. Results: The search yielded seven studies that met inclusion criteria. Each of the seven studies compared CBT to another intervention. Authors' Conclusions: The review found that there was no evidence that CBT interventions perform better or worse than the comparison interventions and additional research is needed. The number of studies included in this review was limited, and therefore should the overall results be interpreted with caution.