ABSTRACT Many youth seek and receive mental health treatment in schools, yet research on their perceptions of these interventions remains uncommon. This qualitative study explored how student perspectives on social validity informed the ongoing implementation and evaluation of the Well-Being Promotion Program (WBPP), a Tier 2 positive psychology intervention in middle schools. The study was conducted during the initial years of a larger ongoing randomized control trial evaluating the WBPP's effectiveness. Themes from student interviews conducted during Year 1 of the larger study were used to inform implementation supports during Year 2 to enhance student acceptability. Thirty student interviews were conducted during Year 2 of the larger study. Overall, most students found the intervention content, group process, and delivery to be acceptable. The findings identified ways to further enhance the implementation of the WBPP and indicate accessing student voice is an important way to engage in program implementation and evaluation of a middle school-based intervention. Recommendations are provided for those interested in centering student voices regarding social validity to inform program implementation and evaluation.