ʿApiru (Ugaritic: 𐎓𐎔𐎗𐎎, romanized: ʿPRM, Ancient Egyptian: 𓂝𓐰𓊪𓐰𓂋𓅱𓀀𓏪, romanized: Ꜥprw), also known in the Akkadian version Ḫabiru (sometimes written Habiru, Ḫapiru or Hapiru; Akkadian: 𒄩𒁉𒊒, ḫa-bi-ru or *ʿaperu) is a term used in 2nd-millennium BCE texts throughout the Fertile Crescent for a social status of people who were variously described as rebels, outlaws, raiders, mercenaries, bowmen, servants, slaves, and laborers.

Due to the linguistic similarity between the term 'Apiru and "Hebrew," early scholars equated them with the Israelites. However, most contemporary scholars now regard the connection as indirect, suggesting that while some early Israelites may have originated from this group, they likely adopted the linguistic label in the process.

The term was first discovered in its Akkadian version "ḫa-bi-ru" or "ḫa-pi-ru". Due to later findings in Ugaritic and Egyptian which used the consonants ʿ, p and r, and in light of the well-established sound change from Northwest Semitic ʿ to Akkadian ḫ, the root of this term is proven to be ʿ-p-r. This root means "dust, dirt", and links to the characterization of the ʿApiru as nomads, mercenaries, people who are not part of the cultural society. The morphological pattern of the word is qatilu, which point to a status, condition.

The Akkadian term Ḫabiru occasionally alternates with the Sumerograms sa.gaz. Akkadian dictionaries for Sumerograms added to sa.gaz the gloss ḫabatu "raider", which raised the suggestion to read the Sumerograms as this word. However, the Amarna letters attested the spelling sa ga.az, and letters from Ugarit attested the spelling sa.gaz, which points that these Sumerograms were read as written and did not function as ideograms. The only Akkadian word that fits such spelling is "šagašu" (barbarian), but an Akkadian gloss to an Akkadian word seems odd, and the meaning of šagašu doesn't fit the essence of the Ḫabiru. Therefore, the meaning of sa.gaz should probably be found in a West Semitic word such as Aramaic šgš, which means "muddy, restless", while the word ḫabatu should be interpreted as "nomad", which fits the meaning of the word Ḫabiru/ʿApiru.

In the time of Rim-Sin I (1822 BCE to 1763 BCE), the Sumerians knew a group of Aramaean nomads living in southern Mesopotamia as sa.gaz, which meant "trespassers". The later Akkadians inherited the term, which was rendered as the calque Ḫabiru, properly ʿApiru. The term occurs in hundreds of 2nd millennium BCE documents covering a 600-year period from the 18th to the 12th centuries BCE and found at sites ranging from Egypt, Canaan and Syria, to Nuzi (Upper Mesopotamia near Kirkuk, northern Iraq) and Anatolia (now Turkey).

Not all Habiru were brigands: in the 18th century BCE, a north Syrian king named Irkabtum (c. 1740 BCE) "made peace with [the warlord] Shemuba and his Habiru," while the ʿApiru, Idrimi of Alalakh, was the son of a deposed king, and formed a band of ʿApiru to make himself king of Alalakh. What Idrimi shared with the other ʿApiru was membership of an inferior social class of outlaws, mercenaries, and slaves leading a marginal and sometimes lawless existence on the fringes of settled society. ʿApiru had no common ethnic affiliations and no common language, their names being most frequently West Semitic, but also East Semitic, Hurrian or Indo-European.

In the Amarna letters from the 14th century BCE, the petty kings of Canaan describe them sometimes as outlaws, sometimes as mercenaries, and sometimes as day labourers and servants. Usually they are socially marginal, but Rib-Hadda of Byblos refers to Abdi-Ashirta of Amurru (modern Lebanon) and his son Aziru as ʿApiru, with the implication that they have rebelled against their common overlord, the pharaoh. In The Taking of Joppa (now Jaffa), an Egyptian work of historical fiction from around 1440 BCE, they appear as brigands, and General Djehuty asks at one point that his horses be taken inside the city lest a passing ʿApir steal them.

Since the discovery of the 2nd millennium BCE inscriptions mentioning the Habiru, there have been many theories linking these to the Hebrews of the Bible. Most of these theories were based on the supposed etymological link and were widely denied basing on the Egyptian sources and later following the Ugaritic and Hittite discoveries. There are two main barriers, linguistic and group identity.