This article seeks to critically assess the relevance of International Relations Theory (IRT) for East Asia International Relations (IR). After identifying the shortcomings of IRT in explaining East Asia IR, the article provides several ways to modify it with a goal to make it more suitable for East Asia IR. Its central claim is that the IRT’s bias toward European experiences and great power politics generates unsatisfactory accounts for and inaccurate predictions about East Asia IR. This does not mean, however, that we should treat IRT as completely irrelevant and develop an indigenous theory of East Asia IR. Given that no single theory is complete and perfectly relevant across time and space and that many core concepts and key variables of IRT are also pertinent for East Asia IR, our efforts should instead be made to refine the existing IRT and make it more suitable for East Asia IR by problematising its major assumptions and central claims on the basis of East Asian experiences. This will save IRT from being a region-specific and a country-specific theory of IR.