Culture matters in social theory construction because the metaphysical component of the theoretical hard core is primarily shaped by the background knowledge of a cultural community. Individual rationality, a key concept abstracted from Western culture, constitutes the nucleus for much of mainstream Western International Relations Theory. This article proposes a relational theory of world politics with relationality as the metaphysical component of its theoretical hard core. It conceives the International Relations (IR) world as one composed of ongoing relations, assumes international actors as actors-in-relations, and takes processes defined in terms of relations in motion as ontologically significant. It puts forward the logic of relationality, arguing that actors base their actions on relations in the first place. It uses the Chinese zhongyong dialectics as its epistemological schema for understanding relationships in an increasingly complex world. This theoretical framework may enable us to see the IR world from a different perspective, reconceptualize key elements such as power and governance, and make a broader comparison of international systems for the enrichment of the Global IR project.