This article presents an agentic theory of human development, adaptation, and change. The evolutionary emergence of advanced symbolizing capacity enabled humans to transcend the dictates of their immediate environment and made them unique in their power to shape their life circumstances and the courses their lives take. In this conception, people are contributors to their life circumstances, not just products of them. Social cognitive theory rejects a duality between human agency and social structure. People create social systems, and these systems, in turn, organize and influence people's lives. This article discusses the core properties of human agency, the different forms it takes, its ontological and epistemological status, its development and role in causal structures, its growing primacy in the coevolution process, and its influential exercise at individual and collective levels across diverse spheres of life and cultural systems.