Different directions of realism theory, as the most prominent theory for studying issues and international relations, are close in several hypotheses and general lines, but when coming to details, they are different. This study examines international questions and environmental issues in particular in terms of these theoretical directions. In general, realistic theories agree on the hypothesis that international issues can be classified into high politics and low politics. But because in today’s world, the dangers and consequences of environmental pollution on international and world security have considerably increased, for this study, main question is that is environment in the perspectives of different directions of realism theory still a minor issue or has its role and position to become a key issue risen, or is it possible to rise? By relying on reliable sources and using each of deductive method, qualitative method and case studies, efforts have been made to investigate and address this scientific question. In order to achieve the goals and giving attention to the cause and the major problem, the study is divided into two main sections, each section includes accurate enquiries. Finally, the study positively proves its hypothesis, which in the perspective of realism theories, issues related to national interest and security are placed at the top of high issues pyramid, while environmental issues are given less importance by the state and international actors. However, at the same time, some differences in the understanding of realism theories are noticed, particularly in defensive realism, which claims that environment should be dealt with as an important subject in some places and stages of time, yet the offensive realism is the most pessimistic one in this aspect.