As reviewed in the article by Perry and colleagues (2014) in this volume, ample evidence has documented the contributions of peer support (PS) to health, health care, and prevention. Building on that foundation, this article discusses characteristics, contexts, and dissemination of PS, including (a) fundamental aspects of the social support that is often central to it; (b) cultural influences and ways PS can be tailored to specific groups; (c) key features of PS and the importance of ongoing support and backup of peer supporters and other factors related to its success; (d) directions in which PS can be expanded beyond prevention and chronic disease management, such as in mental health or interventions to prevent rehospitalization; (e) other opportunities through the US Affordable Care Act, such as through patient-centered medical homes and chronic health homes; and (f) organizational and policy issues that will govern its dissemination. All these demonstrate the extent to which PS needs to reflect its contexts--intended audience, health problems, organizational and cultural settings--and, thus, the importance of dissemination policies that lead to flexible response to contexts rather than constraint by overly prescriptive guidelines.