Adad in Akkadian and Ishkur in Sumerian are the names of the storm-god in the Babylonian-Assyrian pantheon, both usually written by the logogram dIM. The Akkadian god Adad is cognate in name and functions with northwest Semitic god Hadad.

In Akkadian Adad is also known as Ramman ("Thunderer") cognate with Aramaic Rimmon which was a byname of the Aramaic Hadad. (Ramman was formerly incorrectly taken by many scholars to be an independent Babylonian god later identified with the Amorite god Hadad.)

The Babylonian center of Adad/Ishkur's cult was Karkara in the south, his chief temple being E. Karkara and Shala his spouse being worshipped in a temple named E. Durku. But among the Assyrians his cult was especially developed along with his warrior aspect. From the reign of Tiglath-Pileser I (1115–1077 BCE), Adad had a double sanctuary in Assur which he shared with Anu. Anu is often associated with Adad in invocations. The name Adad and various alternate forms and bynames (Dadu, Bir, Dadda) are often found in the names of the Assyrian kings.

The Sumerian Ishkur appears in the list of gods found at Fara but was of far less importance than the Akkadian Adad later became, probably partly because storms and rain are scarce in southern Babylonia and agriculture there depends on irrigation instead. Also, the gods Enlil and Ninurta also had storm god features which decreased Ishkur's distinctiveness. He sometimes appears as the assistant or companion of one or the other of the two.

When Enki distributed the destinies, he made Ishkur inspector of the cosmos. In one litany Ishkur is proclaimed again and again as "great radiant bull, your name is heaven" and also called son of An, lord of Karkara; twin-brother of Enki, lord of abundance, lord who rides the storm, lion of heaven.

In other texts Adad/Ishkur is sometimes son of the moon god Nanna/Sin by Ningal and brother of Utu/Shamash and Inana/Ishtar. He is also occasionally son of Enlil.

Adad/Ishkur's special animal is the bull. He is naturally identified with the Anatolian storm-god Teshub. Occasionally Adad/Ishkur is identified with the god Amurru, the god of the Amorites.