This research evaluated the effects of a seven-session mindfulness intervention, Learning to BREATHE, on an ethnically diverse at-risk high school student sample. Two classrooms were randomly assigned to intervention or normal health-education programming. Results indicated significant effects to self-reported psychosocial resilience, with students receiving the intervention reporting stable levels of resilience over time and students in the control condition reporting significant reductions. Intervention groups did not evidence change to self-reported psychosocial problem behavior, school attendance, and quarterly academic grades. Findings suggest that MBI [mindfulness-based intervention] may offer an effective strategy for enhancing student dispositional resilience, and suggestions for further research are offered.