This article, inspired by the authors’ participation in the research of the Tax Committee of the International Law Association, calls into question the appropriateness of the traditional definition of “tax nexus” and stresses the need to reconcile the existing rules with the principles of international law. It outlines possible avenues for establishing workable, fair and common criteria and rules for the definition of “tax nexus” that operate globally. The article focuses on the existing rules on international tax nexus, inter alia, residence and source, taking into account the principles of public international law, such as those related to tax sovereignty. It proposes the development of a new fair and equitable tax nexus to address the challenges of the globalized modern world, which can potentially draw from the practice in other areas of law, such as competition law. In such a global context, the goal is to verify whether and in which cases multiple criteria for nexus can be replaced with a single nexus based on the concept of the closest connection to a single jurisdiction.