Meta-analyses of mindfulness-based interventions (MBIs) in schools consistently show small, positive effects, but the field remains dominated by studies with low methodological rigour. Recent large randomised controlled trials in adolescents demonstrate poor traction in this age group together with some adverse effects, creating a crossroads for their future. In their recent commentary on the null effects of the MYRIAD trial (Kuyken et al., 2022), Strohmaier and Bailey (2023) postulated that making mindfulness practice available within the school day may increase the dosage and benefits of MBIs for adolescents, and called for funders to direct efforts at developing and testing this approach. We agree that identifying ways to increase dose beyond weekly classroom lessons is important, but explore whether this suggestion is practical or developmentally appropriate for secondary school settings. Our commentary broadens to group together other large and moderately large RCTs that have also shown disappointing results in adolescents, and presents seven barriers that together may be compounding the lack of effect in this age group. We offer alternative suggestions for future school-based research and delivery of MBIs.