Changes in community readiness among key school stakeholders after Ready for Recess

School community readiness (CR) for health promotion efforts may be critical to the effectiveness of school-based interventions aimed at promoting youth physical activity and reducing childhood obesity. The purpose of this study was to: (i) identify key informants who scored highest on school CR at baseline and (ii) determine the effects of Ready for Recess on changes in CR among school key informants from baseline to post-intervention. Key informants (N = 98) across 17 schools participated in CR interviews. Interview questions focused on school CR for physical activity and childhood obesity efforts across six dimensions. At baseline, principals scored higher than teachers in overall readiness and knowledge of the issue and higher than recess staff and nurses in leadership. Leadership readiness decreased across key informants at post-intervention and principals demonstrated greater decreases when compared with recess staff. Baseline disparities between principals and other key informants suggest principals may have overestimated the readiness of staff implementing the intervention. Declines among principals indicate that they may not have been prepared to deliver adequate support to successfully implement the intervention. These results illuminate the importance of assessing/improving school readiness prior to interventions. The CR model may provide an opportunity to improve school-based physical activity interventions.