This article applies theoretical and empirical insights on diffusion to a contemporary, important, and striking case in point: the groundswell of state legislation on and implementation of charter schools over the past decade. Drawing from several data sources and using event-history analyses, competing risks, and random-effects negative binomial regression, the analyses examine how interstate dynamics and intrastate attributes affect the adoption of legislation on and the creation of charter schools within states. The findings reveal a strong mimetic tendency among adjacent states to adopt charter school legislation and regional similarities in the creation of charter schools. Internal attributes of states, such as competition between the private and public school sectors, the relative strength of teachers' unions, the presence of racial competition, urbanization, and political party dominance likewise play a role, depending on whether the analytic focus is on the adoption of legislation or the implementation of policy. The authors conclude by discussing the implications of the results for understanding the forces underlying innovation and change in educational policy.