United Nations Transitional Administration for Eastern Slavonia, Baranja and Western Sirmium

The United Nations Transitional Administration for Eastern Slavonia, Baranja and Western Sirmium (UNTAES) was a UN peacebuilding transitional administration in the Eastern Slavonia, Baranja and Western Syrmia in the eastern parts of Croatia (multicultural Danube river region). The transitional administration lasted between 1996 and 1998. It was also sometimes known as the United Nations Transitional Authority in Eastern Slavonia, Baranja and Western Sirmium. The transitional administration was formally established by the United Nations Security Council Resolution 1037 of January 15, 1996. The transitional administration was envisaged and invited in the November 1995 Erdut Agreement between the Croatian Government and the representatives of the local Serb community in the region. At the time of UNTAES deployment the region already hosted another traditional type UN peacekeeping mission known as the UNCRO. While the region was covered under the UNCRO's sector east (sector led by Russian and Belgian forces), the whole UNCRO mission was brought into question by the Operation Storm escalation of hostilities.

UNTAES is only the third UN peacekeeping mission in history (after UNTEA in Western New Guinea and UNTAC in Cambodia) where the UN assumed direct and high executive powers in the territory of concern. Via UNTAES, the United Nations temporarily took the role of governance in the region by creating an UN protectorate. At the end of the UNTAES deployment an additional monitoring support mission was provided for the region under the name of the United Nations Civilian Police Support Group.