This paper reviews current models, research, and approaches to improving care on the primary care/behavioral health interface in the USA. We focus on care in the public sector where high rates of comorbidity, regulatory burdens, and lack of resources create particular challenges to collaboration and coordination. To achieve the goals of improved coordination and collaboration, it will be critical to address key financing, workforce, information technology, performance assessment, and research issues. It will also be critical to engage multiple stakeholders including consumers, mental health and health providers, and policymakers and public sector funders.