Enbilulu (Sumerian: 𒀭𒂗𒁉𒇻𒇻 ^dEN-bi.lu.lu) was a Mesopotamian god associated with irrigation, and by extension with both canals and rivers. The origin of his name is unknown, and there is no agreement among experts in which way he was related to the similarly named deities Bilulu and Ninbilulu. While originally an independent deity, he eventually came to be seen as a name of Marduk and is mentioned in this role in the Enūma Eliš.

The meaning of the term bilulu is not known, but it appears in two other names of deities as well, Ninbilulu, known from Early Dynastic sources (including the Zame Hymns), and Bilulu, known from the myth Inanna and Bilulu. It has been proposed that there was originally only one deity, Bilulu, who was female and later split into male Enbilulu and female Ninbilulu. However, the identification of Enbilulu and Bilulu is "problematic" according to Wilfred G. Lambert, as "the character of the goddess (...) is not sufficiently similar to that of Enbilulu for the matter to be sure." Another possibility is that Ninbilulu and Enbilulu were the same deity, whose gender either changed after the Early Dynastic period from female to male or who was regarded as male all along. The sign NIN, while conventionally translated as "queen" or "mistress", did not necessarily denote name as belonging to a female deity.

It has been argued that the theoretical original Bilulu was a personification of the storm or of rain clouds. However Enbilulu only rarely is mentioned in association with rain. Frans Wiggermann instead proposes the word bilulu refers to rushes.

Enbilulu was chiefly associated with irrigation and with the water of both canals and rivers. He could be called the "canal inspector of heaven and earth." He has been described as a "purely agricultural deity". Lambert compared him to Enkimdu.

Ninbilulu, who according to Antoine Cavigneaux and Manfred Krebernik might be the same deity as Enbilulu, appears in the Early Dynastic Fara and Abu Salabikh god lists and in a zame hymn from the same period in relation with Tigris, Euphrates and other sources of water, but without a cult center listed. Daniel Schwemer proposes that Enbilulu originally belonged to the pantheon of Eridu. Wilfred G. Lambert considered him to be a deity associated with the city of Babylon. In the Esagil temple complex, a seat was dedicated to him jointly with Enmesharra. It bore the name du₆.ki.sikil, "mound, pure place."

An exorcistic text from the late first millennium BCE assumed to originate in Der lists Enbilulu alongside multiple other agricultural deities, such as Urash, Ennugi and Ningirsu, and implores all of them to protect a field.

A Hittite scribe named Ḫanikkuili, son of a man bearing the Mesopotamian name Anu-šar-ilan, described himself as a servant of Enbilulu in a colophon of a text about Naram-Sin he copied.

In the myth Enlil and Ninlil Enbilulu's parents are the eponymous deities, Enlil and Ninlil, while his brothers are Nanna, Nergal and Ninazu, In other sources he could instead be considered as a son of Ea.