We conducted a two-phase study with ninth-grade high school students (N = 84) who participated in a 10-week mindfulness education program. In phase 1, an intervention was introduced to increase the number of meditation sessions and minutes of formal mindfulness practices they performed. In phase 2, the students completed a social validity assessment by rating their satisfaction with and approval of the mindfulness education program. Intervention had a variable effect with the students and they positively endorsed several outcomes from mindfulness training, particular mindfulness practices, and future interest in mindfulness. We discuss implications from the study for planning and implementing school-based mindfulness education programs.