© 2017 Dr. Lloyd Douglas Freeburn, This thesis challenges the conventional conception of the private law regulatory regime of international sport. That conception is that regulatory authority in international sport is consent-based and exercised by voluntary associations acting through private law contracts. This orthodox conception is untenable. It involves a basic conflict with the categorical nature of regulatory power claimed and exercised in international sport. Further, the incidence of direct contracts between the regulatory bodies and those subject to regulation only covers a small minority of those whose activities are regulated and is inadequate to support the characterisation. Resort to ‘indirect’ contractual links and other legal fictions is also inadequate to support the characterisation. This thesis argues that on proper analysis, international sports governing bodies principally exercise arbitrary de facto private power which is made possible by their monopoly position in sport’s hierarchies and their unique capacity to enforce their own sanctions without requiring support from state legal systems. This de facto power is also supported by the arbitral regime of the Court of Arbitration for Sport. This arbitral regime is permitted to operate by state legal systems in the absence of an arbitration agreement between international federations and those over whom they exercise regulatory power, this concession based on manifestly inadequate justifications. It is also argued that the assumption implicit in the conventional consent-based conception that the de facto power of international sports governing bodies represents the exercise by those bodies of their individual liberty as voluntary associations is incoherent: the scope of individual liberty cannot extend to include non-consensual de facto power over others as this would be defeating of all liberty. The implications of these inadequacies in the conventional conception are amplified by the fact that the regulatory regime of international sport is afflicted by a fundamental legitimacy deficit in that power is exercised by institutions that are neither representative of nor accountable to those who are regulated. In addition to the moral and legal issues raised by the reality of the regime being based on de facto power, institutional corruption in sport is argued to be one consequence of the absence of proper legal and democratic legitimacy. The concern is not that there is private regulatory power in international sport, but that this regulatory power is neither legitimate, nor is it legally sound. Securing a legitimate and legally sound regulatory framework is equally the concern of the international federations as well as those subjected to the federation’s regulatory power. Reforms are required to establish a regulatory regime that is both legitimate and legally sound. However, to be efficacious, these reforms must resolve the tension between international sport’s inherent requirement for the application of uniform and consistent, and therefore categorical regulation, with the prerequisites for the creation of obligations in private law. Reforms based on the introduction of a legitimate regulatory regime based on democracy and legally supported by an international convention are proposed.