To our knowledge, this is one of the first attempts at a comparative analysis of the legal accountability of transnational institutions. We take a broad view on classifying transnational institutions, as including public international organisations (‘IOs’), multinational corporations (‘MNCs’), as well as non-governmental organisations (‘NGOs’). Issues of IO, MNC and NGO accountability can raise a very broad range of concerns, but common challenges exist. Providing access to justice to individuals adversely impacted by transnational institutional conduct is one of those pressing challenges. Accountability gaps for serious environmental damage, breaches of labour standards, and concerns relating to sexual abuse, immediately come to mind. In this Special Issue of the King’s Law Journal, the contributions address various aspects of this accountability gap. At its crux, when allegations of wrongdoing are made against a transnational institution, a threshold question is whether victims have access to a dispute resolution mechanism (‘DRM’) capable of rendering effective justice. As will be observed, such DRMs include not only national courts, but also international mechanisms. The various contributions to this Special Issue address this fundamental question. The comparative exercise undertaken highlights that national courts are not always best placed to adjudicate claims against transnational institutions, and much effort should be placed on creating alternative DRMs for the victims of transnational institutional conduct, with such alternatives capable of rendering effective justice. This is especially the case for claims against IOs which face the additional procedural bar of jurisdictional immunities before national courts (2). As several contributions also show, there seems to be an increasing interaction between access to justice and due diligence obligations increasingly assumed by, or imposed on transnational institutions in general. In this Special Issue, we start to scratch the surface of this very important debate, and hope future research takes up the mantle of further exploring this link (3). Finally, we make some remarks on what may be done to fill the accountability gap in the legal accountability of transnational institutions based on the comparative knowledge gained by considering the various contributions in this Special Issue (4).