Classroom-based curricula represent the primary mechanism by which substance use prevention strategies reach the Nation’s adolescents which is supported by evaluative evidence. However, many schools have not adopted effective prevention curricula. Specifically, “site-based management” (SBM), the center of authority and responsibility for decisionmaking which includes decisions about the adoption of prevention curricula, has been ignored. Drawing on a “site-based management” approach, this study investigated the relative roles of school district and school-level decisionmakers in the implementation of effective substance use prevention curricula. The study hypothesized that when decisionmaking rests with school- and community-based groups, especially classroom-level prevention teachers, schools would be more likely to adopt effective curricula than when the center of decisionmaking resides among administrators at the school district level and schools would be more likely to select and use effective curricula if the schools and associated districts are characterized by shared decisionmaking and high receptivity to change. The study targeted all regular public schools in the 50 States and the District of Columbia that included middle grades. Data were collected from February through September 1999 through the use of questionnaires. The results provide relatively little support for the hypotheses, as well as the benefits of SBM in regard to the adoption of innovations like effective curricula. Support was not found for the hypothesis that vesting decisionmaking in teachers and other school staff results in the selection of effective substance use prevention curricula. However, the advocacy of and pressure from curriculum coordinators in central offices was found as key to the adoption of innovative curricula. In addition, school district-level substance use prevention coordinators were the prime decisionmakers in the adoption of effective curricula in their districts’ middle schools. References