As the OECD and the G20 strengthen their central role in the international tax policy arena, scholars and commentators increasingly question their legitimacy to impose standards and norms worldwide. Calls for greater participation of developing countries led the OECD to introduce the Inclusive Framework. Despite questions about whether such initiative improved normative legitimacy or constituted mere rhetoric to circumvent calls for greater inclusiveness, it illustrates the attention given by policy leaders to the potential legitimacy deficits in the international tax regime. This article analyses the present international tax regime from the perspective of normative legitimacy and argues that despite the importance of improving participation of less powerful countries in international tax policy decisions, increased participation alone may not suffice in making these decisions responsive to interests and needs of developing countries. Structural shortcomings in the institutional design of the international tax regime may require a deeper discussion on what normative principles should guide overall reform of the international tax system in a way that produces a fairer allocation of rights and duties among different stakeholders.