Obesity among US children has risen dramatically in recent decades, and considerable disparities exist by race/ethnicity and socioeconomic status. Research supports the role of the environment in contributing to poor diets, physical inactivity, and obesity and environmental and policy interventions are being widely promoted to combat this epidemic. Bridging the Gap (BTG) is one of the key contributors to this growing body of research. BTG examines the impacts of state, local and district-level policies as well as school and community characteristics and environmental conditions on youth behaviors and weight outcomes and on disparities in them. T Project goals include interpretation of long-term trends in student obesity and related behaviors from Monitoring the Future (MTF); surveys of middle and high school administrators in MTF schools and in a supplementary sample of 600 public schools to enable accurate national trend estimates. BTG’s purpose is to generate new information and knowledge relevant to childhood and adolescent physical inactivity, unhealthy eating, and obesity that will stimulate and inform policy change at various levels (schools, school districts, communities, states, nationally). BTG also helps to assess progress over time.