Background: The school environment, consisting of the physical environment and social-emotional climate (SEC), plays a crucial role in both student and employee health; however, there is a lack of recent literature synthesizing school environment interventions in K-12 settings. We describe updated evidence about school environment interventions to support K-12 student and employee health in the United States. Methods: A 2-phase search included a review of reviews (2010-2018), followed by a search for individual articles (2010-2020) that targeted school physical environment and/or SEC to address physical activity (PA) and/or nutrition. We also investigated how nutrition and PA interventions with an SEC component improves social-emotional and/or mental health outcomes. Because research on dietary and PA behaviors for school employees is limited; we included studies on other worksites (eg, hospitals and offices) to provide insight for school employees. Findings: We identified 40 articles describing 40 unique studies and 45 interventions and grouped them by intervention type. Physical environment interventions demonstrated significant and positive nutrition and PA behavioral outcomes for students; outcomes among employees were mixed. Interventions with SEC components reported improvements in some mental health outcomes. Implications: The school environment can affect dietary and PA behaviors as well as mental health for students and employees. Conclusions: Establishing healthy school environments can support student and employee PA, dietary behaviors, and mental health.