This dissertation evaluates the impact of elementary school policies on child health behaviors and obesity in the United States. Two chapters address nutrition policies, two chapters address physical activity policies, and a final chapter estimates the health care cost savings associated with a decline in childhood obesity prevalence. The use of large national datasets allows for the investigation of disparities by child, school and regional factors. This is in contrast to other studies which are based on a limited geographic area or small, demographically homogeneous samples. Policymakers have promoted restrictions on competitive foods, which are subject to minimal federal regulations and typically have low nutrient value. I find that many states implemented a limit or nutrition standard between 2004 and 2007 and that these policies have had the intended effect of limiting sugar-sweetened beverages and increasing the availability of low-fat snacks and sweets in schools. While restrictions on availability are associated with lower school-based consumption, no impact on obesity is found. Plausible explanations include that children respond to restrictions by substituting purchases from outside of school and that children's purchasing power increases as they age. In regards to physical activity, I find that children from disadvantaged backgrounds are more likely to attend schools with poorer gymnasium and playground provision. Furthermore, having a gymnasium is associated with more time in physical education class. A related analysis finds suggestive evidence that an expansion of physical education and recess programs to meet national recommendations would mitigate body mass increase. While school policies are a promising tool for obesity prevention, few interventions have proven effective. However, even a small effect could imply sizeable health benefits over the life-course. Estimates from my simulation model suggest that a 1% decline in childhood obesity would result in lifetime savings of about $1 billion. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]