Background: As summarized in this article, the widespread implementation of modern school health education (SHE) could become one of the most effective means available to improve the well-being of people in the United States and in other nations. However, the development and evolution of SHE largely remains unorganized, underdeveloped, and neglected by health and education agencies, policymakers, and the public. Methods: Essential to the development of any scientific discipline, scientists today use the word ontology to refer to efforts to organize knowledge in particular domains. A useful working definition of a scientific ontology is an explicit, formal specification of a shared conceptualization--a systematic set of shared terms and an explication of their interrelationships. Nine interdependent questions are outlined to help guide the development of an initial, broad, and actionable scientific ontology for SHE. Results: Whether and how we respond to these questions arguably will determine the future of SHE research, policy, practice, and equity in the United States. Conclusions: An initial ontology might help conceptualize, inform, and facilitate more systematic and strategic local, state, national, and international deliberations and actions to improve SHE.