Damu (Sumerian: 𒀭𒁕𒈬) was a Mesopotamian god. While originally regarded as a dying god connected to vegetation, similar to Dumuzi or Ningishzida, with time he acquired the traits of a god of healing. He was regarded as the son of the medicine goddess Ninisina, or of her equivalents such as Gula or Ninkarrak. It is unclear which city was originally associated with him, but he is best attested in association with the cult center of his mother, Isin.

Damu is also a theophoric element in many personal names from Ebla. It has been proposed that in this context the term should be understood as a deified kinship group rather than a deity, and it is assumed it is not connected to the Mesopotamian god.

It is assumed that Damu was originally regarded as a dying god. In that capacity, he might have been associated with trees. He was most likely envisioned as a child, possibly an infant, in contrast with other dying gods who were instead described as young men, and were often referred to with the term g̃uruš, conventionally translated as "lad". Dina Katz suggests that high rates of infant mortality in antiquity influenced traditions pertaining to him, and that the rare examples of passages referring to him as g̃uruš might be the result of conflation of various similar gods.

From the Old Babylonian period onward, Damu was known chiefly as a healing deity instead. This aspect of his character is absent from texts pertaining to his death, which according to Katz might indicate that his character had been altered at some point, likely in the Old Babylonian period. She proposes that the change might had been facilitated by the loss of his original cult center and relocation of his clergy to Isin, where he was incorporated into the circle of the city goddess Ninisina and acquired similar traits as a result; she assumes that the laments which connect the dying Damu with the medicine goddess were composed later. Irene Sibbing-Plantholt instead suggests that Damu originally developed alongside Gunura as an independent deity personifying healing, and in later periods took a role complementary to that played by goddesses associated with this sphere of activity, such as Ninisina.

As a deity linked to healing, Damu could be called an asû, "physician". He could be described as familiar with medicinal plants, as attested in a text from the reign of Sin-Iddinam. It was believed that he was able to find cures for diseases which were regarded as incurable due to this knowledge. As indicated by the incantation Ninisina, mother of the land, he was especially closely associated with care for strings (sa), a term possibly referring to sinew, muscles or blood vessels, envisioned as a single net-like system. There is also evidence that he was regarded as capable of healing headaches (di'u) and the unidentified ašû disease. An incantation refers to him as bēl tākalātim, literally "lord of pouches", though it is presumed the term tākaltu in this context refers to an internal organ, possibly specifically the stomach. A further epithet applied to him was bēl balāṭi, "lord of life", which might hint at a belief that he was able to revive the dead.

Damu's attribute in the role of a medicine god was a karzillu knife, identified as a scalpel by Barbara Böck. Sibbing-Plantholt tentatively suggests that other symbols associated with him might have been a dog and a crook, as they are depicted on a seal with an inscription mentioning him.

In Mesopotamian astronomy, Damu was associated with the constellation Pig. It has been suggested that it might have consisted of stars today regarded as the head and first coil of Draco, though this interpretation is not certain.

It is not possible to determine with which deity or deities Damu was originally associated. In earliest god lists, he is typically listed alongside the deities of the state of Lagash, though from the Old Babylonian period onward he started to be placed in the court of Ninisina instead. In the Ur III period, he could be linked to Gula, as attested in offering lists from Ur, but he was also recognized as one of the deities of Isin, in which capacity he was associated with Ninisina instead. His character as a healing deity was also highlighted in particular when he was associated with the latter. Irene Sibbing-Plantholt argues that initially Damu and Gula were paired only as deities whose characters were seen as complementary, and only Ninisina in addition to a similar association was also viewed as his mother. While the latter role is attested for Gula too, for example in the god list An = Anum (tablet V, line 165), it only developed later on. In some bilingual texts, Gula and Damu are instead used as corresponding deities in the two versions. A connection between him and Ninkarrak, also based on similar character and complementary roles in healing, is also known. However, references to Ninkarrak being his mother, while known, are rare. Exclusively in Nippur he was also associated with Nintinugga, as attested in sources from the Ur III period. Dina Katz additionally points out that a lament calls Damu's mother Geshtinluba, the Emesal version of the name of said goddess.