Allani, also known under the Akkadian name Allatu (or Allatum), was the Hurrian goddess of the underworld. She was also associated with the determination of fate. She was closely linked with Išḫara, and they could be invoked or receive offerings together. She also developed connection with other underworld deities from neighboring cultures, such as Mesopotamian Ereshkigal (who eventually came to be equated with her), Anatolian Sun goddess of the Earth and Lelwani, and possibly Ugaritic Arsay. It is presumed she was chiefly worshiped in western areas inhabited by the Hurrians, though the location of her main cult center is uncertain. She is attested in texts from sites such as Tigunani, Tuttul and Ugarit. She was also incorporated into the Mesopotamian pantheon, and was venerated in Ur, Nippur and Sippar. Hittite sources mentioning her are known too.

The theonym Allani has Hurrian origin and consists of the word allai, lady, and the article -ni. It has been noted that simple epithet-like theonyms were common in Hurrian tradition, another well attested example being Šauška, "the great". In texts written in the Ugaritic alphabetic script, Allani's name was rendered as aln. The Akkadian form is Allatum. In 1980 Wilfred G. Lambert proposed that Allatum, who he understood as the same deity as Ereshkigal in origin, was the feminine counterpart, and possibly wife, of a minor Mesopotamian god associated with the underworld, Alla. However, Gernot Wilhelm [de] already stated in 1989 that no convincing Akkadian etymology has been proposed for the name Allatum, and it is now agreed that it was a derivative of Allani. Alfonso Archi suggests this form of the name originally developed in Syria, and from there reached Mesopotamia. In Emar, an ancient city in Syria, both forms were used. A further variant, Allantum, is attested in texts from Tigunani. It differs from the usual variant Allatum, but also represents a combination of the base Hurrian name with the Akkadian feminine suffix.

Allani was regarded as the queen of the underworld in Hurrian religion. According to Hurrian texts, she resided in a palace at the gate of the "Dark Earth" (Hurrian: timri eže), the land of the dead. As an extension of this role she was also one of the deities who took part in the determining of fates of mortals. She could be referred to with the title "the bolt of the earth", negri ešeniwe. This epithet reflected her association with the underworld, with the word "earth" functioning as a euphemism. Another title applied to her was šiduri, "young woman". She was accordingly imagined to have had a youthful appearance. As indicated by texts pertaining to the ḫišuwa [de] festival, she was believed to wear a blue garment, with the color presumably being associated with death.

Like two other of the most commonly worshiped Hurrian goddesses, Išḫara and Shaushka, Allani was regarded as unmarried. A single text mentions a "daughter of Allatum", which according to Volkert Haas constitutes the only reference to this goddess having children. Piotr Taracha [de] identifies the daughter in mention as Ḫepat, but according to Lluis Feliu, it is possible Shalash was considered her mother.

An association between Allani and Hurrian primeval deities is also attested. This group was believed to dwell in the underworld.

Allani was often invoked alongside Išḫara, who also was associated with the underworld in Hurrian religion. The connection between these two goddesses is already present in documents from the Ur III period. In the ritual of Allaituraḫi, Allani is invoked alongside Išḫara to protect a household from demonic forces. Instructions for the ḫišuwa [de] festival mention the clothing of statues representing Allani and Išḫara, with the former receiving a blue garment and the latter an identical red one. Veneration of them as a pair was an example of a broader phenomenon frequently attested in Hurrian sources, the worship of pairs of deities with similar purposes as if they constituted an unirty, with other examples including Šauška's attendants Ninatta and Kulitta, the fate goddesses Hutena and Hutellura, Ḫepat and her son Šarruma, and the astral deities Pinikir and DINGIR.GE₆, so-called Goddess of the Night. In some cases Allani and Išḫara could receive a single offering jointly.

Another Hurrian goddess connected to the underworld who sometimes appears in the proximity of Allani was Shuwala, though she was more commonly associated with Nabarbi. Edward Lipiński argues that Shuwala was the same deity as Allani, but they appear together as two distinct deities in texts from Ur and Hattusa.

Presumably due to her own role as a deity associated with fate, Allani was associated with Hutena and Hutellura.