Ashur-uballit II (Aššur-uballiṭ II), was the last king of the Assyrian empire. He reigned in the last capital city of Harran from 612 BC to 609 BC, having fled Nineveh during the siege and capture of that city by the Babylonian-Median army in 612 BC.
In alliance with Egyptian forces, Ashuruballit's army was able to defend Harran from the combined Babylonian-Median attack for a brief period following the destruction of Nineveh; however, when the Egyptian army had to return their homeland in 610 BC, the Babylonians and Medians swept into Harran and sacked it.
Assyria again called upon Egypt, who came to their assistance. King Josiah of Judah allied himself with Babylon and tried to block the way of the forces of Egypt under Pharaoh Necho II. Josiah was defeated at Meggido, and was killed in the battle. Pharaoh Necho marched on together with Ashur-uballit II, to besiege Harran. They were defeated and the Egyptians retreated into northern Syria. Ashur-uballit II disappears from history, bringing an end to the Assyrian empire. It is probable that he was killed in this 2nd siege of Harran in 609 B.C.
While it is clear that he was a member of the Assyrian royal family, and that he was a tartan of the Assyrian army before declaring himself king, there is some disagreement as to whether or not Ashur-uballit II was the brother of Sinsharishkun who ruled the empire from 623 BC to 612 BC. He took his name from Ashur-uballit I, the Assyrian king who overthrew Mitannian domination in about 1330 BC, and began the Middle Assyrian era (1330 BC-1076 BC).