This study is designed to significantly advance empirical research on school wellness policies: focused on implementation and measurable impact on student health. No matter how well written, a school wellness policy must be effectively implemented to achieve its potential impact. Further, students within schools represent only two components of a larger socio-ecological system that influences eating behavior, physical activity, and weight status. The federal mandate for school wellness policies requires districts to address many aspects of the school environment (e.g., nutrition education, nutrition standards for foods sold, and opportunities for physical activity). To maximize improvements, this type of multi-component policy is needed. However, this complexity makes it difficult to evaluate policy impact and draw conclusions about the causal relationships between specific policies and student health. With our team's unique strengths and these challenges in mind, we designed this research study with the following Specific Aims: