Extraterritoriality at the ECtHR appears to create a paradox. On the one hand, it is limited in space, time, purpose and remedies, through its state membership, individual application process, the terms of the ECHR, and restricted enforcement and influence on general international policy. On the other, it appears to be an indispensable refuge for individuals who are victim to the most flagrant denials of justice happening on a global scale. The ECtHR finds itself an avenue for redress in historical events of global significance such as the NATO bombing and UN administration of Kosovo, the US-UK occupation in Iraq, extraordinary rendition procedures and the interception of migrant boats at sea. This thesis embraces the paradox of extraterritoriality at the ECtHR. Putting forward a normative framework, the thesis clarifies the nature of extraterritoriality at the ECtHR and investigates the extent to which the ECtHR adopts a single normative frame. Existing theories fail to capture the nature of extraterritoriality in the ECtHR’s operation. This thesis offers a global constitutionalist approach to deduce a model for extraterritoriality. Using a normative global constitutionalist frame, in particular democratic accountability and the rule of law, the thesis examines the extent to which the ECtHR adopts such an approach. Translating the requirements of normative global constitutionalism into doctrinal indicators, it examines whether the ECtHR operates within a global constitutionalist frame in extraterritoriality decisions. Alongside this examination, the thesis queries the function and purpose of extraterritoriality and its relationship with other international legal concepts. It questions models that rely on state jurisdiction and attribution to determine their extraterritorial reach, exposing extraterritoriality as performing a separate function. It ultimately unravels the paradox of extraterritoriality through a global constitutionalist explanation.