Sukkal (conventionally translated from Sumerian as "vizier") was a term which could denote both a type of official and a class of deities in ancient Mesopotamia. The historical sukkals were responsible for overseeing the execution of various commands of the kings and acted as diplomatic envoys and translators for foreign dignitaries. The deities referred to as sukkals fulfilled a similar role in mythology, acting as servants, advisors and envoys of the main gods of the Mesopotamian pantheon, such as Enlil or Inanna. The best known sukkal is the goddess Ninshubur. In art, they were depicted carrying staves, most likely understood as their attribute. They could function as intercessory deities, believed to mediate between worshipers and the major gods.

The office sukkal is also known from various areas to the west and east of Mesopotamia, including the Hurrian kingdom Arrapha, Syrian Alalakh and Mari and Elam under the rule of the Sukkalmah Dynasty, while the concept of divine sukkals was incorporated into Hurrian religion, in which major gods such as Kumarbi or Hebat commonly appear in company of their sukkals, similar to their Mesopotamian counterparts.

The word sukkal (Akkadian: sukkallu) has Sumerian origin and at first denoted a class of human officials, responsible for the implementation of the commands of the king. Translations found in literature include "vizier", "secretary", and "chancellor." Tonia Sharlach notes that "vizier" is considered to be the standard translation today. The same word is also conventionally employed as a translation of the name of another, unrelated, office, badalum, used in northern Syrian cities, such as Harran and Abarsal, in the third millennium BCE. It is also the conventional term for the head of the Eblaite administration, most likely referred to as lugal sa-za. The word sukkal is attested in Eblaite documents, but seemingly designates a type of clergyman instead.

This office of sukkal is also known from outside southern Mesopotamia, for example from Mari from Alalakh in western Syria, from the Hurrian kingdom of Arrapha in northeastern Mesopotamia, and from Elam. At least in southern Mesopotamia and Mari, a sukkal served as an intermediary between the royal administration and foreign envoys. There is evidence that they often knew more than one language and acted as translators, and some were likely foreigners or children of foreigners who settled in Mesopotamia. In some cases, a specific foreign dignitary was always mentioned alongside the same local sukkal accompanying him.

A related office, known from Early Dynastic Girsu and from the administrative texts of the Third Dynasty of Ur, was that of the sukkalmah (GAL.SUKKAL, sukkalmaḫḫu). Tonia Sharlach proposes this term should be understood as the equivalent of a modern secretary of state. A sukkalmah was in charge of a number of sukkals. In Elam, this term was adopted as a royal title, possibly because the sukkalmahs of the Ur III state, who resides in Lagash, close to Elamite territory, were in charge of the territories surrounding Susa when the state they served reached its maximal extent. The so-called Sukkalmah Dynasty ruled over Elam in the early second millennium BCE.

Some lexical texts explain sukkal as pašišu, "salve priest", though the reason behind the equation of these two terms is not known.

In Mesopotamian religion, some deities were designated as sukkals and functioned as a divine counterpart of the human officials. Due to more direct evidence present in myths compared to economic and administrative texts, their functions are better known than these of their human namesakes. A sukkal was the highest-ranked member of a deity's court, and in some cases in god lists could appear even before their children. At the same time, not every servant deity was a sukkal. Three distinct classes of divine servants can be found in various documents: advisers and representatives (including the sukkal), deities dealing with the personal needs of a god, and finally those tasked with upkeep of their household, such as divine cooks or gardeners. In myths, sukkals act both as traveling envoys of their masters, and as their advisors at home. Wisdom was frequently regarded as a trait of this class of deities. While most deities had courtiers, usually only these whose position in the pantheon was well established had sukkals, and sukkals of the major city gods were likely the oldest deities of this type. Instances of a sukkal having a sukkal of their own, while known, should be regarded as an anomaly according to Richard L. Litke. For example, Niĝgina, a sukkal of the sun god Utu, had her own sukkal, as did Alammuš, the sukkal of the moon god Nanna.

The goddess Ninshubur is regarded by Assyriologists as "the earliest and most important" sukkal, the "archetypal vizier of the gods."