Prevention support systems (PSSs) are designed to help communities implement evidence-based practices (EBPs). Little is known about the factors that influence their adoption. In this article, we examined adoption of a PSS for substance abuse prevention called Getting To Outcomes (GTO)[R] among staff in two community coalitions with varying levels of exposure to it over a 2-year period. A multistage regression model was used to determine the relative predictive power of organizational, innovation-related, and practitioner characteristics on adoption. Findings indicate that GTO adoption occurred through increased exposure, especially via staff training. Perceptions of the system's complexity moderated this effect. Individuals with high GTO exposure were less likely to adopt it if they perceived it as complex. Other organizational, innovation-related, and practitioner characteristics did not predict adoption. Results from this study are useful for understanding the factors associated with PSS adoption and suggest ways to increase their use in typical delivery settings. (Contains 2 tables and 1 figure.)