Mindfulness training for youth is growing tremendously across the nation; however, few studies rigorously assess its effects. Studies that employ mindfulness training have shown promise in increasing emotional and cognitive regulation among youth, including those who are highly vulnerable. Rigorous controlled trials are vital for increasing our understanding of the efficacy of mindfulness-based interventions for vulnerable youth, the variety of methods for delivering mindfulness training, and how attention to normative and non-normative developmental trajectories impact both implementation and study outcomes. The presentations at this symposium describe recent and ongoing randomized controlled trials of mindfulness training for a wide age range of adolescent youth who are dealing with challenging life circumstances, including involvement in the criminal justice system, coping with HIV/ AIDS, and residing in neighborhoods with the highest rates of poverty and violence. The presentations will be followed by a guided, interactive discussion between the discussant, presenters, and the audience.