Mindfulness-based interventions (MBIs) in schools have become increasingly popular, as these practices can be integrated into classrooms by teachers, adapted to fit the individual needs of students or groups of students, and implemented as a schoolwide commitment to improve well-being. Research shows that MBIs are broadly effective for improving a variety of social, emotional, behavioral, and academic outcomes for diverse students. However, implementation of MBIs in under-resourced schools presents a unique set of challenges for school staff. This paper addresses this issue constructively by providing guidelines for increasing access to MBIs in under-resourced schools. First, we provide a brief overview of common ecological barriers--and potential solutions--to implementing MBIs in under-resourced schools at the individual-level, team-level, school-level, and macro-level. This overview is followed by recommendations for de-implementing outdated interventions and implementing MBIs instead. Finally, we complete our guidelines by describing the Adapting Strategies to Promote Implementation Reach and Equity (ASPIRE) framework and how this heuristic can be applied to guide culturally sensitive and equity-focused adaptations to MBIs in under-resourced schools.