The relationship between EU law and double taxation conventions is usually approached assuming the existence of a conflict; rarely is the issue raised and accurately investigated whether or not EU law could assist in the interpretation of those conventions. In this paper, it is submitted that this can be the case where the interpretation of terms not defined in double taxation conventions is at stake. The conclusion drawn after investigation is that EU law can indeed play such a role according to article 31(3)(c) of the 1969 Vienna Convention on the Law of Treaties and/or toarticle 3(2) of the OECD Model Tax Convention on Income and on Capital. Some examples of possible applications of this approach are also proposed in this paper, particularly that of beneficial ownership, and one may expect that the continuing evolution of EU law will likely increase the number of relevant cases.