Meditation training programs for adolescents are predicated on the assumptions that mindfulness and self-compassion can be directly cultivated, and further, that doing so is beneficial for emotional well-being. Yet, very little research with adolescents has tested these assumptions directly. In the current study, I examined longitudinal relationships between changes in mindfulness and self-compassion and changes in emotional wellbeing among healthy, but stressed adolescents who participated in five-day, intensive meditation retreats. Immediately before and after the retreats, and then three months later, 132 adolescents (M-age = 16.76 years, 61% female) completed questionnaires measuring mindfulness, self-compassion, and emotional well-being. Repeated measures ANOVA showed adolescents improved in mindfulness, self-compassion, and all indices of emotional well-being immediately following the retreat (Cohen's d = vertical bar 0.39-1.19 vertical bar, and many of these improvements were maintained three months later (Cohen's d = vertical bar 0.04 - 0.68 vertical bar). Further, multilevel growth curve analyses with time-varying covariates indicated within-person changes in self-compassion predicted enhanced emotional well-being more consistently than within-person changes in mindfulness. Specifically, increases in self compassion predicted reductions in perceived stress, rumination, depressive symptoms, and negative affect, and conversely, increases in positive affect and life satisfaction (pseudo-R-2 variance explained = 5.9% and 15.8%, ps < 0.01). (C) 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.