Slave raiding is a military raid for the purpose of capturing people and bringing them from the raid area to serve as slaves. Once seen as a normal part of warfare, it is nowadays widely considered a war crime.^{[citation needed]} Slave raiding has occurred since antiquity. Some of the earliest surviving written records of slave raiding come from Sumer (in present-day Iraq). Kidnapping and prisoners of war were the most common sources of African slaves, although indentured servitude or punishment also resulted in slavery.

The many alternative methods of obtaining human beings to work in indentured or other involuntary conditions, as well as technological and cultural changes, have made slave raiding rarer.^{[citation needed]}

Slave raiding was a large and lucrative trade on the coasts of Africa, in Europe, Mesoamerica, and in medieval Asia. The Crimean–Nogai slave raids in Eastern Europe provided some two or three million slaves to the Ottoman Empire via the Crimean slave trade over the course of four centuries. The Barbary pirates from the 16th century onwards through 1830 engaged in razzias in Africa and the European coastal areas as far away as Iceland, capturing slaves for the Muslim slavery market in North Africa and West Asia. The Atlantic slave trade was predicated on European countries endorsing and supporting slave raiding between African tribes to supply the workforce of agricultural plantations in the Americas.

The act of slave raiding involves an organised and concerted attack on a settlement with the purpose of taking the area's people. The collected new slaves are often kept in some form of slave pen or depot. From there, the slave takers will transport them to a distant place by means such as a slave ship or camel caravan. When conquered people are enslaved and remain in their place, it is not raiding.^{[citation needed]}

During the Middle ages, Saracen Andalusian pirates established themselves in bases in southern France, the Baleares, Southern Italy and Sicily, from which they raided the coasts of the Christian Mediterranean and exported their prisoners as Saqaliba slaves to the slave markets of the Muslim West Asia.

The Aghlabids of Ifriqiya was a base for Saracen attacks along the Spanish East coast as well as against Southern Italy from the early 9th century; they attacked Rome in 845, Comacchio in 875-876, Monte Cassino in 882-83, and established the Emirate of Bari (847–871), the Emirate of Sicily (831–1091) and a base in Garigliano (882-906), which became bases of slave trade. During the warfare between Rome and the Byzantine Empire in Southern Italy in the 9th century the Saracens made Southern Italy a supply source for a slave trade to Maghreb by the mid-9th century; the Western Emperor Louis II complained in a letter to the Byzantine Emperor that the Byzantines in Naples guided the Saracens in their raids toward South Italy and aided them in their slave trade with Italians to North Africa, an accusation noted also by the Lombard Chronicler Erchempert.

Moorish Saracen pirates from al-Andalus attacked Marseille and Arles and established a base in Camargue, Fraxinetum or La Garde-Freinet-Les Mautes (888–972), from which they made slave raids in to France; the population fled in fear of the slave raids, which made it difficult for the Frankish to secure their Southern coast, and the Saracens of Fraxinetum exported the Frankisk prisoners they captured as slaves to the slave market of the Muslim Middle East.

The Saracens captured the Baleares in 903, and made slave raids also from this base toward the coasts of the Christian Mediterranean and Sicily.