OBJECTIVES: Gun violence is a significant problem in the United States of America. Gun violence produces lifelong psychological adversity, trauma, and grief. In the face of this epidemic, efficacious therapies that assuage gun violence-based trauma and negative health are lacking. METHODS: The proposed, longitudinal pilot experiment examined the effects of an 8-week mindfulness-based stress reduction (MBSR) program on traumatized individuals as a direct consequence of gun violence. Twenty-four victims of gun violence (median age = 53 years; 21 female) completed measures of the primary outcome: trauma. Secondary outcomes were characterized as grief, depression, sleep quality, life satisfaction, and mindfulness. All assessments were administered before, after 5, and 8 weeks of MBSR training. It was hypothesized that trauma and other comorbidities would improve following MBSR. It was also predicted that outcomes would be significantly stronger from baseline to 5 weeks of MBSR training than from 5 to 8 weeks of training. RESULTS: Before MBSR, volunteers exhibited high levels of trauma, depression, sleep difficulty, and grief. Participation in MBSR was associated with improved trauma, depression, sleep difficulty, and life satisfaction. The most pronounced improvements in psychological disposition were exhibited within the first 5 weeks of MBSR. However, these benefits were largely preserved after completion of the course. Importantly, increases in dispositional mindfulness predicted lower trauma, complicated grief, and sleep difficulties. CONCLUSIONS: The present findings should be interpreted with caution because they were derived from an uncontrolled, non-randomized trial. However, said findings suggest that MBSR may reduce trauma and improve overall well-being in gun violence victims.