The health promotion field is often criticized for focusing on lifestyle change while ignoring contextual forces that influence health. Social ecological models recognize individuals as embedded within larger social systems and describe the interactive characteristics of individuals and environments that underlie health outcomes (Sallis, Owen, & Fisher, 2008;Stokols, 1992). More than 20 years ago, an issue of this journal was dedicated to the exploration of an ecological model for health promotion. Building on the work of Urie Brofenbrenner (1977), who had previously articulated a multilevel framework, McLeroy, Bibeau, Steckler, and Glanz (1988) offered five levels of influence specific to health behavior: intrapersonal factors, interpersonal processes and primary groups, institutional factors, community factors, and public policy.In addition to articulating level-specific influences on health behavior, the authors described possible intervention strategies at each level of influence (McLeroy et al., 1988). What is particularly important, they argued, is to conceptualize model levels as more than just settings for interventions. Specific individual and environmental changes sought by a program help identify the level of intervention. For example, the authors suggest that intrapersonal level interventions aim to change the knowledge, beliefs, and skills of individuals. Interpersonal-level and institutional-level interventions, by contrast, are designed to create change in social relationships and organizational environments. The authors propose that changes in communities derive from partnerships with agencies, churches, neighborhoods, and other mediating structures; the objective of community-focused interventions is usually to increase health services or empower disadvantaged groups. Finally, implementing public policies with health behavior implications or facilitating citizen advocacy are frequent targets of interventions at the public policy level.Ecological models assume not only that multiple levels of influence exist but also that these levels are interactive and reinforcing. Stokols (1992Stokols ( , 1996 argues that the social, physical, and cultural aspects of an environment have a cumulative effect on health. He further contends that the environment itself is multilayered, since institutions and neighborhoods are embedded in larger social and economic structures, and that the environmental context may influence the health of individual people differently, depending on their unique beliefs and practices. Creating sustainable health improvements, therefore, is most effective when all of these factors are targeted simultaneously. Stokols (1996), however, notes that influencing all aspects of the environment Abstract Social ecological models that describe the interactive characteristics of individuals and environments that underlie health outcomes have long been recommended to guide public health practice. The extent to which such recommendations have been applied in health promotion interventions, however...