The International Criminal Tribunal for the Former Yugoslavia (ICTY) was established in 1993 and commenced its activities in 1994. Since then, it has prepared and tried dozens of cases involving allegations of war crimes, crimes against humanity and genocide in the former Yugoslavia, accumulating a staff of more than 1,000 persons over several years, at the cost to the United Nations of some USD 120 million per year. The investment by the international community and states in the efforts of the Tribunal to bring persons responsible for core international crimes to criminal justice has been extraordinary. At the same time, the sincerity and intensity of the efforts made by the Tribunal’s staff to fulfill its mandate can not easily be criticized. Nevertheless, there has been limited acceptance of the ICTY by governments and people in the former Yugoslavia where the alleged crimes were committed. What are the reasons for this? How do we measure the impact of the ICTY on territorial states? Has the ‘outreach activities’ of the ICTY failed? Why? What should be the effect of the existence and work of the ICTY on the territorial states? Whose responsibility is it to ensure that this effect is achieved: the Tribunal, the governments of territorial states, other governments, civil society? Which lessons can be learned from this aspect of the interaction between the Tribunal and the states and peoples in the areas affected by the crimes?