In their joint fight against tax avoidance and tax evasion, international governance organizations have developed different tools. One of these tools is the joint tax audit, in which two or more countries join together to form a single audit team to examine an issue(s)/transaction(s) of one or more related taxable persons with cross-border business activities. International governance organizations, such as the Organisation for Economic Co-operation and Development (OECD), the European Union and the African Tax Administration Forum (ATAF), promote the use of joint tax audits, amongst others, as a tool in fighting tax fraud, tax evasion and aggressive tax planning. The literature on this phenomenon mainly focuses on the advantages and obstacles of using the instrument, and the need to amend legislation. Moreover, in the literature, guidance for companies invited to participate in a joint tax audit can be found, as well as references to the few joint tax audits conducted and the results of a pilot project conducted by the Netherlands and Germany. The authors’ aim is to answer the question, “Which countries may benefit most from joint tax audits if the arguments raised in the tax literature are valid?”. The authors have identified eight arguments for joint tax audits (arguments (a) – (h), see sections 4.1. and 5.) in the tax literature and have used sixteen different yardsticks (factors 1 – 16, see section 6.) to analyse which countries might benefit most. To make the research project manageable, the research focuses primarily on the situation faced by the European Union’s 28 Member States (hereinafter the “EU-28”) As Croatia joined the European Union as the 28th Member State in 2013, the public finance data provided in this article refer to the EU-27. Eleven of the 16 factors refer to EU-28 public finance data. The exception is the number of taxpayers’ factor because of available data for Croatia before 2013. The remaining 5 provide data before 2013, thus concern to EU-27 (see Table 8). and the 13 associated states. By combining arguments raised in the legal literature about joint audits with what public finance data tell us about, for example, tax compliance costs, the number of active taxpayers per administration employee, the number of mutual agreement procedures, tax compliance and tax moral levels, the authors analyse which of the EU-28 and its associated states might benefit most from joint audits and for what reasons. The analysis strongly supports the international governance initiatives for a multilateral legislative framework on joint audits. As multinational legislation in this field should be drafted with great care, the authors call for more pilot projects with, as their aim, the sharing of know-how and building capacity. The authors also provide some recommendations for the development of the multinational legislative framework and urge tax authorities/the OECD/the European Union to publish statistics on the joint audits performed.