This study examined whether stigma toward mental illness decreased for youth after participating in focus groups in a school-based mental health promotion program called Youth Net (YN FGs). A total of 294 students from 6 high schools participated in a randomized controlled trial, completing questionnaires that measured stigma and depression. Stigma decreased for participants in the intervention group in low-need schools only. Study findings suggest continuing with YN FGs in low-need schools and working collaboratively with community partners to provide evidence of the effectiveness of mental health promotion with youth.