In the 1990s, the promise of justice for atrocity crimes was associated with the revival of international criminal tribunals (ICTs). More recently, however, there has been a renewed emphasis on domestic accountability for international crimes across the globe. In identifying a 'complementarity turn', a paradigm shift toward domestic accountability in the field of international criminal justice, this book investigates how the shadow of international criminal tribunals influences the treatment of serious crimes at the national level. Drawing on research and interviews in Rwanda, the Democratic Republic of Congo, and Sierra Leone, this book develops a tripartite framework to analyse how states and tribunals work with, despite, or against one another in the fight against impunity. While international prosecutors and judges use the principle of complementarity to foster cooperation and decrease tension with government actors, Patryk I. Labuda argues that too much deference by ICTs toward states reduces the likelihood of accountability and may enable national elites to consolidate authoritarian power. By interrogating how international accountability stakeholders relate to their domestic counterparts, International Criminal Tribunals and Domestic Accountability advocates improvements to ICTs' institutional design and more dynamic interactions with states to strengthen the enforcement of international criminal law.