When veterans need effective mental health treatment, many are reluctant to engage in traditional treatment modalities because of stigma. Therapeutic adventure shows promise as a way to engage veterans and enact positive changes in functioning, but little is known about how therapeutic adventure impacts mental health symptoms among veterans. This study examined changes in mental health symptoms and related psychological processes over the course of a 6-day Outward Bound for Veterans (OB4V) program and at a 1-month follow-up. This study examined data from 77 U.S. military veterans with psychiatric diagnoses. The authors hypothesized that participants would report significant reductions in mental health symptoms over the course of the program and following its completion, as well as significant improvements in psychological processes that included initiative for psychological growth, psychological attitudes, attitudes toward help-seeking, psychological mindedness, and emotional suppression. A repeated-measures analysis of variance was performed on each of the dependent variables. Results showed that, from pre- to postprogram, participants reported significant improvement in life purpose satisfaction and self-confidence during stressful situations. Further, from preprogram to 1-month postprogram, veterans reported increased psychological mindedness, increased engagement to promote personal growth, decreased mental health symptomology, decreased emotional suppression, and an increase in positive attitude toward seeking professional psychological help. These improvements were significant during the OB4V program and even continued to improve after the program ended, showing the promise of therapeutic adventure as a modality to address veterans' mental health issues. (PsycINFO Database Record (c) 2019 APA, all rights reserved).