Youth raised in high poverty neighborhoods are frequently exposed to stressful situations, such as community violence and family conflict, that adversely affect their well-being and academic performance. School-based mindfulness programming may support student functioning, however the existing research contains several limitations (e.g., lack of intervention replication and weak experimental designs). The goal of this project is to rigorously assess the impact of a promising intervention, “Learning to BREATHE” (L2B), on the inner well-being of at-risk high school students. Four health education classrooms from an urban public high school located in a high-poverty community were randomly assigned to L2B intervention or normal health education class. Longitudinal (i.e., data collection pre-L2B, post-L2B, and at 1-month follow-up) multi-informant (i.e., student self-report, parent/guardian and teacher report on student) data were collected on student social and relational behaviors, self-awareness, well-being, and academic performance. Students received L2B in the fall of 2016, and data is currently being analyzed. This research will potentially demonstrate the benefits of school-based mindfulness programming, and it will serve as a catalyst for further use of mindfulness programming in this and other schools, and will spur further investigation and large-scale research initiatives.