Adolescents spend a large proportion of their day in school or pursuing school-related activities. While the primary purpose of school is the academic development of students, its effects on adolescents are far broader, also encompassing their physical and mental health, safety, civic engagement, and social development. Further, its effects on all these outcomes are produced through a variety of activities including formal pedagogy, after-school programs, caretaking activities (e.g., feeding, providing a safe environment) as well as the informal social environment created by students and staff on a daily basis. While most reports focus on a particular aspect of the school environment (e.g., academics, safety, health promotion), this brief looks at schools more comprehensively as an environment affecting multiple aspects of adolescent development. Research has repeatedly demonstrated the interconnectedness of the pieces, with safety and health affecting the academic environment, academics affecting health and social development, and so on. For that reason, any particular aspect of school policy and activities will be better understood through the lens of that larger context. This is particularly important as school systems have become even more pressured to focus on their main goal of academic development as a result of the federal No Child Left Behind initiative. This brief is designed to be of particular interest to school principals, district staff, and others who are responsible for all aspects of school functioning. It should also be useful to those focusing on a narrower range of school functions (e.g., academics, health and safety, civic development) who want a better sense of how their concerns fit into the larger environment. This brief present national estimates from a variety of sources on the school environment of adolescents in the areas of health, safety, social support, academics, and civic engagement. (Contains 8 figures and 1 map.) [This Research Brief is a product of a partnership between Child Trends and the National Adolescent Health Information Center (NAHIC) at the University of California, San Francisco.]