The global financial crisis of 2008 and the following public uproar over offshore tax evasion and corporate aggressive tax planning scandals gave rise to unprecedented international cooperation on tax information exchange and coordination on corporate tax reforms. At the behest of the G20, the OECD developed a comprehensive package of ‘consensus-based’ policy reform measures aimed to curb base erosion and profit shifting (BEPS) by multinationals and to restore fairness and coherence to the international tax system. The legitimacy of the OECD/G20 BEPS Project, however, has been widely challenged. This paper explores the validity of the legitimacy concerns raised by the various stakeholders regarding the OECD/G20 BEPS Project.