Substance abuse researchers identify self-efficacy and group cohesion as important components in alcohol and other drug-dependency treatment. Objectives: The purpose of this single-group, pretest-posttest study is to explore the therapeutic value of a challenge course intervention on the self-efficacy and group cohesion of nine chemically dependent, adult females. Methods: Data were collected using two validated outcome measures administered before and after the intervention. Focus groups provided insight into the experiences of participants and were examined using manifest and latent theme analysis. Results: Findings indicate statistically significant improvements on both outcome measures with medium to large effect sizes. Several themes were identified including group unity, trust, interpersonal growth, and self-confidence. Conclusions: Suggestions for practice and future research are provided. (Contains 1 table.)