Akkadian or Mesopotamian royal titulary refers to the royal titles and epithets (and the style they were presented in) assumed by monarchs in Ancient Mesopotamia from the Akkadian period to the fall of the Neo-Babylonian Empire (roughly 2334 to 539 BC), with some scant usage in the later Achaemenid and Seleucid periods. The titles and the order they were presented in varied from king to king, with similarities between kings usually being because of a king's explicit choice to align himself with a predecessor. Some titles, like the Akkadian šar kibrāt erbetti ("king of the Four Corners of the World") and šar kiššatim ("king of the Universe") and the Neo-Sumerian šar māt Šumeri u Akkadi ("king of Sumer and Akkad") would remain in use for more than a thousand years through several different empires and others were only used by a single king.
In the Akkadian-speaking kingdoms of Assyria and Babylonia, distinct styles of Akkadian titulature would develop, retaining titles and elements of earlier kings but applying new royal traditions. In Assyrian royal titulary, emphasis would typically be placed on the strength and power of the king whilst Babylonian royal titulary would usually focus on the protective role and the piety of the king. Monarchs who controlled both Assyria and Babylon (such as some of the Neo-Assyrian kings) often used "hybrid" titularies combining aspects of both. Such hybrid titularies are also recorded for the only known examples of Akkadian titularies beyond the fall of the Neo-Babylonian Empire, employed by Cyrus the Great (r. 559–530 BC) of the Achaemenid Empire and Antiochus I (r. 281–261 BC) of the Seleucid Empire, who also introduced some aspects of their own royal ideologies.