People engaged in efforts to improve services to emerging adults with serious mental health challenges have reached the conclusion that service change at the program or agency level is not sustainable without related changes at the systems or policy level. This article focuses on one set of efforts to create intentional system change at both the community and state levels. These changes were pursued by states and communities that received grants under the federally funded Healthy Transitions Initiative (HTI), with the aim of creating more effective services for emerging adults with serious mental health conditions. The article reviews the development of a measure to assess systems change efforts at the state and community levels and describes the findings that emerged when the measure was used to assess the change that occurred in the HTI sites over a period of approximately three and a half years.