This chapter deals with the transparency of decision-making that establishes international military operations, the accountability of individual actors, and the responsibility of the institutions creating the mandates for such operations. It begins with an overview of the sources of internationally mandated use of force, including the United Nations and regional arrangements. It then turns to UN operational and legal milestones in carrying out international mandates for peace operations. The chapter also discusses changes in national accountability mechanisms by citing the episodes in Somalia, Rwanda, and the Balkans. Finally, it reviews the 2000 Report of the Panel on Peace Operations that revealed the complexity of transparency, accountability, and responsibility with respect to internationally mandated military operations.