Arbitration has always been viewed as a preferable method of dispute resolution in cross-border trade, due to its effectiveness, privacy and enforceability. Yet, one issue that persists in arbitration law is the treatment of parties who are directly involved in the ‐underlying transaction, even if they are not signatories to the arbitration agreement. This paper is driven by the important question of whether it is legally legitimate and practically useful to permit such non-signatories to join in the arbitral process. What ultimately occupies the heart of this dissertation is the “Group of Companies” doctrine – itself a big debate in arbitration law. It is a seemingly flexible way to bind non-signatory affiliates in the right circumstances; however, its application is not consistently recognized throughout every jurisdiction. Most recently, Indian courts, particularly in Cox and Kings Ltd. v. SAP India Pvt. Ltd, adopted the “Group of Companies” doctrine opening up the door for a more adaptable and realistic framework to apply in arbitration. But with the significant caveat of the continued questions regarding the “Group of Companies” doctrine’s declaratory element and its enforceability with consideration to international conventions. This article aims to provide a comprehensive and comparative analysis of the joinder of non-signatories in international arbitration, with a particular focus on the Indian legal landscape.