Ilaba was a Mesopotamian god. He is best attested as the tutelary deity of the kings of the Akkadian Empire, and functioned both as their personal god and as the city god of Akkad. Textual sources indicate he was a warlike deity, frequently described as armed with a mace. Whether he was understood as a fully independent deity or as a deified ancestor, as well as his proposed connection to the similarly named Ugaritic ancestral deity Ilib, remain a matter of dispute among researchers. He is not mentioned in any sources predating the reign of Sargon of Akkad. After the end of the Akkadian Empire, he continued to be worshiped in various cities in Mesopotamia, for example Mari, and in the Old Babylonian period he became the tutelary deity of the rulers of the Kingdom of Khana. He also continued to appear in literary texts describing the feats of Akkadian rulers and in god lists.

Ilaba's name was written in cuneiform as 𒀭𒀀𒂷 Ìl-a-ba₄, DINGIR.A.MAL. It is understood as a combination of the elements il, the generic word "god" or a distinct theonym, and aba, "father," attested in Semitic languages, and can be translated as "Il is the father" or "Il, the father." In the past Assyriologists were uncertain how to read it, and possibilities such as ^dA.MAL or ^dA.BA₄ were proposed. Attempts were also made to identify the god meant as Zababa or Marduk. The correct reading has been first established in 1969 by Åke W. Sjöberg and found acceptance in Assyriology in subsequent decades.

Ilaba was the city god of Akkad. It is assumed that he functioned as a war deity. A mace is often mentioned in association with him. An inscription of Sargon known from an Old Babylonian copy states that Ilaba's weapon let him triumph over fifty other rulers. Another relays that Ilaba received his mace from the head of the pantheon, Enlil. In texts from the reign of Naram-Sin, he often appears alongside another warlike deity, Annunitum, who is designated as the one "leading the troops of the city of Ilaba" in one case. It has been argued that they were regarded as spouses, but this remains uncertain.

Manfred Krebernik notes that while it remains a matter of debate in scholarship if Ilaba was an individual deity or simply a generic term for a family god or a deified ancestor, the fact that his character is described consistently in known sources, his association with a specific city, and his presence in god lists seem to support the former view. Jack M. Sasson states that the view that he represented a deified ancestor, similar to deities such as Itūr-Mēr or Yakrub-El, is common in scholarship, though he considers it implausible himself. A connection between Ilaba and Ugaritic divine ancestral figure Ilib has been proposed by Wilfred G. Lambert. However, Dennis Pardee argues the character of Ilib cannot be considered identical with Ilaba's, and rules out the possibility that the former was derived from the latter. Krebernik notes that accepting that Ilib was derived from Ilaba would require assuming that the name of this god was translated after he was introduced into the Ugaritic pantheon.

Sargon of Akkad referred to Ilaba as his personal god. No evidence of the worship of Ilaba predates the period of this king's reign, including toponyms and theophoric names. One of his successors, Naram-Sin, referred to Ilaba as illat-śu, literally "his clan," perhaps to be understood metaphorically as "protector" or "family deity," though he called Enlil his personal god.

An inscription of Naram-Sin states that after extending his empire in the west he "smote the people whom the god Dagān had given to him for the first time, so that they perform service for the god Ilaba, his god." The mention of Dagan is typical for Sargonic inscriptions dealing with western conquests, as this god was believed to be responsible for bestowing kingship in the Upper Euphrates area, as also attested in later texts from Mari. It is not certain if the reference to the inhabitants of the northwestern territories having to serve Ilaba indicates that he was introduced to this area by the Sargonic dynasty, or if he was present in the local pantheon before already. The original of the discussed text was apparently inscribed on a monument located in Ur, but it is known to modern researchers from an Old Babylonian copy. A curse accompanying this inscription invokes Ilaba alongside a large number of other deities, such as Sin, Nergal, Ninkarrak, Ninhursag and Nisaba. Ilaba is also one of the five Mesopotamian deities mentioned in a treaty between Naram-Sin and an unknown ruler of Elam, the other four being Išḫara, Manzat, Ninkarrak and Ninurta. A text which is either a copy of an inscription of Naram-Sin or a later literary composition describing a rebellion against this king lists Ishtar, Ilaba, Shullat and Hanish, Shamash, and Umshu as the deities he reports the defeat of the rebels to.

A year name of Shar-Kali-Sharri states that he built a temple dedicated to Ilaba in Babylon before defeating a Gutian king named Sharlak. However, its ceremonial name is unknown. Andrew R. George argues that Ilaba shared it with Annunitum, but according to Paul-Alain Beaulieu, while the same year name mentions both of these deities, it commemorates the building of two separate temples. As of 2017, this year name remained the oldest known reference to the city of Babylon, in this case written as KÁ.DINGIR^ki (the first sign is read as babu in Akkadian, the second as ilu, the third is a determinative designating place names), a spelling also well attested in later times, seemingly reliant on a folk etymology reinterpreting the city's name as "gate of the gods." A temple of Ilaba might have also existed in Sippar, while an ereš-dingir priestess dedicated to him resided in Girsu. A reference to sanga clergy of Ilaba is known too.

Two texts from Susa mention offerings made to Ilaba and the deity ^dšu-nir, interpreted as a deified standard by Piotr Steinkeller and Manfred Krebernik, but as Bēlat-Šuhnir by Ran Zadok. Based on the content of the texts in mention, Steinkeller assumes the palatial administration of Susa was dedicated to Ilaba.