Produced in partnership with SustainableED, this brief synthesizes research on how to teach Planetary Health, the interdependence of human health and the health of Earth's natural systems. Because research on Planetary Health in K-12 settings is still emerging, it also draws on the literature on environmental and climate change education. The brief explains why the subject is hard to teach and identifies five evidence-based practices: professional development that helps teachers practice specific strategies, instruction that is personally and locally relevant, a focus on solutions and collective action, structured dialogue and psychological safety, and nature-based outdoor learning. It also cautions against steering students toward predetermined answers and relying on scientific knowledge alone. Each section offers ideas for how school and district leaders and teachers might apply the findings, and the brief highlights how partners and coalitions can support this work.