The concept of agency has become widely used in education, social sciences, psychology, and more. This article explores the concept of agency and provides a critical review from two main bodies of work: The social cognitive theory and the structure agency theory. The two are not the same. Structure agency theory was used to illuminate agency from an organizational perspective. Social-cognitive theory was used to better understand leader agency from a social perspective. In order to understand the relationship between structure agency and leader agency, both of these theories are reviewed through the same lens: agency within the workplace, mainly in school structure and school leadership. Conclusions are drawn to a better understanding of how to develop a school leadership agency. We can summarize that the implications of agency in school are the key to effective school leadership.