This paper aims to examine the potential role of conflict of laws, or private international law, in coordinating the relation among different treaties in public international law. In particular, it focuses on the conflict of rules and principles between WTO law and the United Nations Educational, Scientific and Cultural Organization (UNESCO) Convention on the Protection and Promotion of the Diversity of Cultural Expressions (hereinafter the Cultural Diversity Convention, or the CDC). The creation of the 2005 CDC has generated a risk of conflict between its rules and principles and those of WTO law—an example of a “conflict of regimes” in the “fragmentation of international law.” While there have been several discussions in public international law doctrine on the relation between the WTO and the CDC, it is remarkable that a recent academic work adopts some approaches in the conflict of laws doctrine to proposes a solution to the WTO—CDC conflict. Mainly examining the recent work by Dirt Pulkowski, the author of the paper arguers that a conflict of laws perspective would be useful in analyzing the nature of regime conflicts and detecting possible problems inherent in “inter-systemic” or regulatory conflicts. In particular, the basic framework for analyzing regulatory conflicts, that is, the distinction of false and true conflicts, could help the interpreter deal with seemingly irreconcilable rule conflicts as false ones. In short, the conflict of law doctrine could contribute to the conflict management of different international law branches as an analytical perspective.