In this chapter, we define the field of International Relations and provide a comprehensive overview. We outline the foundational premises of International Relations and clarify the essential concepts that define the discipline. Furthermore, we explore the prevalent theories within international relations, commonly referred to as “isms.” Recently, there has been a tendency for these “isms” to generate scholarship that prioritizes academic output over practical application, leading to their exclusion from educational environments due to negative implications. While the author acknowledges this trend, there is a recognition of the critical importance of not entirely omitting the teaching of “isms.” Consequently, we aim to raise awareness of this issue by briefly introducing two “isms” as valuable frameworks for understanding international relations.