The present chapter examines self-regulation across the life span with a focus on integrating cognition and emotion. First, we situate self-regulation in a theoretical context and describe the conceptual foundations that have informed its study across multiple sources of influence, settings, and over time. We then discuss how self-regulation has been defined and operationalized in diverse fields over the life span including developmental, personality, cognitive, and educational perspectives. Next, we review measurement issues including the what, where, and how to assessing self-regulation from a multidimentional perspective. Finally, we discuss the development of self-regulation over the life span and conclude the chapter with common themes, implications, and future directions for research and intervention.