This study was conducted as part of a comprehensive 5-year national evaluation of Communities in Schools (CIS). Using a quasi-experimental design this study intended to examine the effects of CIS on graduation and dropout rates. The sample included 123 high schools matched to non-CIS schools within the same state. Results indicated that initiatives that aim to prevent student dropout by encouraging collaboration between schools and their communities can keep students on track to graduation. High fidelity CIS schools had stronger outcomes than CIS schools that partially implemented the model.