On December 5, 2019, the Roundtable on Population Health Improvement of the National Academies of Sciences, Engineering, and Medicine convened a workshop to explore the factors that affect the health and well-being of middle-school-aged adolescents. The workshop included presentations on the risk factors of poor physical, social, and emotional outcomes and their prevalence; the identification of resilience factors; current policies and programs designed to support middle school success and address issues of equity and financing as they apply to these; and how the health and human services sectors can support and align with the education sector to promote health and well-being in middle school. This publication summarizes the presentations and discussions that took place during the workshop. Table of Contents Front Matter 1 Introduction 2 To Thrive in Middle School and Beyond, and the Middle School Years, a 360 View 3 Remarks from the Mayor of Oakland and Middle School Inside Out 4 Multisector Support for the Middle School Experience 5 The Big Picture 6 Reflections on the Day and Closing Remarks Appendix A: References Appendix B: Workshop Agenda Appendix C: Biosketches of Speakers and Moderators