Children's physical inactivity is an important health concern, and, as suggested, school efforts can be important in increasing activity. The purpose of this study was to use collective efficacy as a framework to examine elementary classroom teachers' and principals' perceptions about integrating physical activity. Three hundred fourteen elementary teachers and 38 school principals completed survey information to assess variables related to their efficacy in activities to promote physical activity. Participants acknowledged the importance of children's physical activity and their willingness to integrate movement. Willingness to integrate was related to individual and collective efficacy, but personal involvement in physical activity was not. Mastery experiences were most influential in predicting strength of individual efficacy; institutional environment was the strongest of collective efficacy. (Contains 6 tables.)