Policy makers and providers are under increasing pressure to find innovative approaches to achieving better health outcomes as efficiently as possible. Accountable care, which holds providers accountable for results rather than specific services, is emerging in many countries to support such care innovations. However, these reforms are challenging and complex to implement, requiring significant policy and delivery changes. Despite global interest, the evidence on how to implement accountable care successfully remains limited. To improve the evidence base and increase the likelihood of success, we applied a comprehensive framework for assessing accountable care implementation to three promising reforms outside the United States. The framework relates accountable care policy reforms to the competencies of health care organizations and their health policy environments to facilitate qualitative comparisons of innovations and factors that influence success. We present emerging lessons to guide future implementation and evaluation of accountable care reforms to improve access to and the quality and affordability of care.