This chapter reflects on the contribution health sociology can make to an understanding of health behavior and health promotion in the context of public health research and advocacy. It begins with a short history of public health to demonstrate the shift in focus of interventions over time from structural interventions to individual behavior change. After interrogating the concepts of health behavior and health promotion, and how they relate to each other, the discipline of health sociology and the key debates with which the discipline is concerned will be introduced. The chapter will argue that a valuable contribution health sociology can make to health behaviors and health promotion is the broad concept of “practice theories.” These are a cluster of theoretical explanations that can illuminate an understanding of health behavior and include the theory of “lifeworlds” and of “lifestyles.” The theory of “lifeworlds” is based on the work of Habermas but has been applied to explain contemporary health behavior. Similarly, the theory of “lifestyles” is based on the work of Bourdieu but has been further developed to explain the collective nature of health behavior. There is some overlap in these theories, and they can be considered together as “practice theories” to represent health behaviors as the result of complex social structures and interactions. A counter point of view that posits that individual (rather than collective) responsibility for health behavior should be emphasized will also be considered. Finally, practice theories will be applied to the example of obesity to demonstrate how these theoretical concepts can expand an understanding of health promotion and health behaviors in relation to a complex, persistent health issue.