Theory and practice must co-exist. Everyone, including leadership scholars, educators, and practitioners, all use theory every single day. Although we often do not realize it, theory is an important way we make meaning from the world around us. This chapter discusses the importance of theories, especially for leadership studies. While theories are not laws, or rules we must abide by, they provide boundaries and parameters for us to make sense of the world around us. In leadership we tend to have theories, approaches, and models, which are all tied to how we learn and how the brain processes. This chapter makes theories more approachable and useful.