We randomly assigned 71 student participants to an acceptance and commitment therapy (ACT) group training or to a wait list. All participants completed measures at preintervention, 1-month postintervention, and 2-month follow-up. Students receiving ACT exhibited significantly reduced levels of general psychological distress and negative emotional symptoms at follow-up. Mental health outcomes for ACT were mediated by increases in psychological flexibility and mindfulness. Results suggest that ACT group training could be an effective mental health intervention in educational settings.