A growing body of evidence suggests that mindfulness meditation is associated with a number of physiological and psychological benefits in both adult and juvenile populations. Research on mindfulness-based interventions among at-risk and incarcerated youth populations has also shown feasibility as a means of enhancing self-regulation and well-being. This randomized controlled trial examined an 8- to 12-week program in which participants received individual and group psychotherapy. Participants in the experimental condition received formal mindfulness training alongside psychotherapy, while those in the control condition received psychotherapy without mindfulness training. All participants received the group intervention. Participants were recruited from a court-mandated substance abuse group treatment program at a juvenile detention camp in the San Francisco Bay Area. Participants were 35 incarcerated youth (100 % male; 70 % Hispanic; mean age = 16.45). Of these, 27 provided complete pre- and post-treatment assessment data. Measures of mindfulness, locus of control, decision-making, self-esteem, and attitude toward drugs were administered before and after the intervention. Detention camp staff provided behavioral rating points for each participant in the week prior to beginning the study treatment and in the week after completing the intervention. Significant increases in self-esteem (p < 0.05) and decision-making skills (p < 0.01) were observed among the entire study sample. Between-group analyses found significantly greater increases in self-esteem (p < 0.05) and staff ratings of good behavior (p < 0.05) in the mindfulness treatment group, consistent with prior research. These results suggest a potentially important role for mindfulness-based interventions in improving well-being and decreasing recidivism among this at-risk population.