The past three decades have seen increasing concern in the international community for the need to more effectively 'do justice’ for victims of mass atrocities. At the same time, there is a growing recognition that such justice includes, together with the need to ensure that appropriate reparation is provided to victims, the criminal accountability of those responsible for the most serious crimes. This thesis argues that there is an intrinsic relationship between these two emerging values. In particular, it demonstrates that a right to justice, understood as the right to the determination of the individual criminal responsibility of wrongdoers, is emerging under international law as an imperative remedy for victims of gross human rights violations and international crimes, alongside more traditional forms of reparation. The development of victims’ right to justice invites a reconsideration of the role and the rights of victims in criminal proceedings. It is argued that if victims have a right to the prosecution of human rights offenders as an integral component of their right to remedy, it is legitimate to assert that they should also be granted corresponding procedural rights in the criminal process. Through an extensive review of international legal instruments and practice and a comparative analysis of domestic criminal justice systems, this study demonstrates that the role of victims and the rights they possess in criminal proceedings have considerably expanded during the past three decades. The most significant development can be found in the law and practice of international and internationalized criminal tribunals, where procedures have been introduced aimed at enabling victims to participate in the proceedings. The incorporation of a regime of victim redress within the framework of international criminal tribunals not only represents an extension of the mandate of international criminal justice but also confirms a shift in the way in which redress is conceptualised at the international level.