Background: In this study, we describe state agency strategies to support weight-related policy implementation in schools, and examine the association among state support, obesity prevalence, and strength of state policies governing school nutrition and physical education. Methods: The 2012 School Health Policies and Practices Study describes prevalence of implementation support state agencies provided to schools/districts. Implementation support items were analyzed by weight-related policy area (e.g., advertising, wellness policy) and by type of support (e.g., technical assistance). Results were summed to create a total weight-related policy support score. Linear regression was used to examine associations between policy support and state youth obesity prevalence (2011-2012 National Survey for Children's Health), overall and stratified by state policy strength (2012 Classification of Laws Associated with School Students). Results: States provided support most commonly for school meals and wellness policies (89% and 81%, respectively) and least often for after-school PE (26%). Most states (80%) provided technical assistance. The total weight-related policy support score had a significant positive association with state-level youth overweight/obesity prevalence (p = 0.03). Conclusions: State agencies appear to be responding to their youth obesity prevalence with technical support. Schools and state agencies should work in collaboration to provide a healthy school environment for all students.