The Iazyges (/aɪˈæzɪdʒiːz/) were an ancient Sarmatian tribe that traveled westward in c. 200 BC from Central Asia to the steppes of modern Ukraine. In c. 44 BC, they moved into modern-day Hungary and Serbia near the Pannonian steppe between the Danube and Tisza rivers, where they adopted a semi-sedentary lifestyle.

In their early relationship with Rome, the Iazyges were used as a buffer state between the Romans and the Dacians; this relationship later developed into one of overlord and client state, with the Iazyges being nominally sovereign subjects of Rome. Throughout this relationship, the Iazyges carried out raids on Roman land, which often caused punitive expeditions to be made against them.

Almost all of the major events of the Iazyges, such as the two Dacian Wars—in both of which the Iazyges fought, assisting Rome in stopping the Dacians' incursions into Roman conquered territory in the first war and defeating the Dacians in the second—are connected with war. Another such war is the Marcomannic War that occurred between 169 and 175, in which time, the Iazyges fought against Rome but were defeated by Marcus Aurelius and had severe penalties imposed on them.

Although the Iazyges were nomads before their migration to the Tisza plain, they became semi-sedentary once there, and lived in towns, although they migrated between these towns to allow their cattle to graze. Their language was a dialect of Old Iranian, which was quite different from most of the other Sarmatian dialects of Old Iranian. According to the Roman writer Gaius Valerius Flaccus, when an Iazyx became too old to fight in battle, they were killed by their sons or, according to Roman geographer Pomponius Mela, threw themselves from a rock.

The Iazyges' name was Latinized as Iazyges Metanastae (Ἰάζυγες Μετανάσται) or Jazyges, or sometimes as Iaxamatae. Their name was also occasionally spelled as Iazuges. Several corruptions of their name, such as Jazamatae, Iasidae, Latiges, and Cizyges, existed. Other modern English forms of their name are Iazyigs, Iazygians, Iasians, and Yazigs. The root of the name may be Proto-Iranian *yaz-, "to sacrifice", perhaps indicating a caste or tribe specializing in religious sacrifices.

According to Peter Edmund Laurent, a 19th-century French classical scholar, the Iazyges Metanastæ, a warlike Sarmatian race, which had migrated during the reign of the Roman Emperor Claudius, and therefore received the name of "Metanastæ", resided in the mountains west of the Theiss (Tisza) and east of the Gran (Hron) and Danube. The Greek Metanastæ (Greek: Μετανάσται) means "migrants". The united Scythians and Sarmatæ called themselves Iazyges, which Laurent connected with Old Church Slavonic ѩзꙑкъ (językŭ, "tongue, language, people").

The graves made by the Iazyges were often rectangular or circular, although some were ovoid, hexagonal, or even octagonal. They were flat and were grouped like burials in modern cemeteries. Most of the graves' access openings face south, southeast, or southwest. The access openings are between 0.6 metres (2 ft) and 1.1 m (3 ft 7 in) wide. The graves themselves are between 5 m (16 ft) and 13 m (43 ft) in diameter.

After their migration to the Tisza plain, the Iazyges were in serious poverty. This is reflected in the poor furnishings found at burial sites, which are often filled with clay vessels, beads, and sometimes brooches. Iron daggers and swords were very rarely found in the burial site. Their brooches and arm-rings were of the La Tène type, showing the Dacians had a distinct influence on the Iazyges. Later tombs showed an increase in material wealth; tombs of the 2nd to early 4th centuries had weapons in them 86% of the time and armor in them 5% of the time. Iazygian tombs along the Roman border show a strong Roman influence.