The present study aimed to clarify the connectivity and complementarity of relative and universal affairs in international relations. Believing that, based on the “ unity despite plurality” approach, it is possible to have one worldview despite the plurality of methods, it would be possible to have the basic, fixed, general, and universal principles, despite having secondary, multiple, diverse, numerous, changing, and specific models and rules based on uncertainty and evolution in the relative universality theory. The article tries to extrapolate the theory of « relative universality » developed by Jack Donnelly as regards the concept of human rights to the main concepts of IR such as sovereignty, State, power, security, gain, national interest, order and values. In response to the question of why the IR concepts are universal and absolute in their pivotal core as well as relative and contextual in their fluid, soft and gelatinous shell, the article concludes, through an explicative method, that it is due to the paradoxical nature of glocalization era in which the dialectics of unity in values and plurality in methods leads to the mutual construction and dynamics interaction of particularity and generality in the framework of « relative universality ».