A prevalent institution of the Islamic world throughout its history, slavery (ʿubūdīyah, riqq) had a crucial influence on societies and cultures of Islam.

Slavery was common in pre-Islamic and contemporary societies in the Mediterranean basin, Asia, and Africa. Early Islamic dogma assumed its existence as part of society and set out to mitigate the conditions of human bondage. Islamic law defined slavery as an intrusive practice: it forbade the enslavement of free members of Islamic society, including dhimmīs (non-Muslims) residing in the abode of Islam. The sharīʿah (divine law) regarded as legal slaves only those non-Muslims who were imprisoned or bought beyond the borders of Islamic rule, or the sons and daughters of slaves already in captivity. Furthermore, Islam's contention that man is basically free (al-aṣl huwa al-ḥurrīyah) forbade the enslavement of foundlings and orphans. The manumission of slaves (ʿitq) was condoned as a meritorious act. Islamic law offered several procedures of manumission through a declaration, a will, or a grant of enfranchisement.

The legal status of slaves was somewhat obscure. From a legal viewpoint slaves (male slaves were termed ʿabd, mamlūk, raqīq, asīr, or ghulām; female slaves were usually termed jāriyagh or fatāh) were both persons and the properties of others. Slaves were not to be mutilated or killed by their master. Yet the master owned the slave's labor and property and was entitled to his or her sexual submission. Slaves could be bought and sold at the owner's will. A slave was not entirely responsible for his or her actions and was not expected to adhere to the same rigid codes of conduct demanded of a free Muslim. In criminal cases slaves were punished less severely than free Muslims, and sometimes the law required that their master be punished in their stead. In practice (though not always according to the letter of the law) slaves had a right to a certain amount of personal property during their lifetime. On their death, however, any such property reverted to the owner.

Under ʿAbbāsid rule (749–1258 C.E.) these elaborate legal injunctions of the sharīʿah developed alongside other state institutions, not always in complete accord. In practice, slavery deviated from the rules laid down by the sharīʿah. The introduction of slave soldiers (mamlūk) into the retinues of rulers created a new kind of slave, one that was a member of the political elite, more a master than a slave. Military slavery developed into a major institution of the Islamic world and reached its apex in the Mamlūk sultanate (1254–1517), in which slaves became the rulers of the state. Side by side with the military institution, domestic and agricultural slavery continued to exist. 

The Ottoman Empire inherited the entire spectrum of Islamic slavery and adjusted it to its own needs. From the fifteenth century onward the Ottomans modified military slavery, raising periodic levies of Christian youths (devşirme) from villages inside the empire's territory, formally enslaving and converting them to Islam and finally incorporating them into the sultan's service. After rigorous training and socialization, these recruits (kul, kapı kulları) became the Ottoman ruling elite. Although the imperial palace had a monopoly on this unorthodox method of enslavement, other Ottoman officials, imitating the sultan's household, maintained a parallel recruitment pattern of slaves from abroad, and an elaborate hierarchy of slaves: trained kul and other mamlūks, concubines, eunuchs (khādim, khaṣī), and valets of all kinds. From the sixteenth century to the end of the nineteenth century slaves rose to the most prominent positions in the state. From this time onward, even free Muslims of old families who wished to enter high-level positions would sometimes request to become “slaves of the pādishāh.”

The majority of slaves were still used in domestic service. Menial workers were to be found in the houses of the upper and middle classes. In the city and the countryside slaves were also used in industry and sometimes in agriculture. They served as oarsmen and pearl divers in the southern seas, and as plantation laborers in Egypt, Iraq, Yemen, or Africa. Such a disparity necessarily created a continuum, at the extremes of which were two types of slaves. The kul were to become the social and political elite of master-slaves, while at the other extreme chattel slaves, most often termed köle, were employed in the most profane tasks and suffered harsh conditions. The same was true for female slaves—from concubines who became the sultans’ consorts to slaves used for domestic and agricultural manual labor. Although mobility along the parallel social ladder of slavery was possible, the move from one extreme to the other, hinging as it did on ascribed statuses of color and race, was uncommon. Yet all kinds of slavery, regardless of the differences in status, were united by the harshness of the slave trade, by the abrupt dislocation of the slave from family and society, and by the almost total domination of slave by master. Similar models of slavery on a somewhat smaller scale existed in the other large Islamic empires of the time—the Mughal state in India and the Ṣafavids in Persia. In Islamic Africa chattel slavery, mainly female, was more common.

From the fifteenth century to the eighteenth century several thousand slaves reached the Ottoman Empire every year by caravan or ship from Africa, the Caucasus, and eastern Europe. At the beginning of the nineteenth century the slave trade veered southward. The Russian conquest of the Caucasus and the Crimea, along with repeated defeats in the Balkans, compelled the Ottomans to look for new markets in Africa. This trend was emphasized by the policy of Muḥammad ʿAlī, the rebellious pasha of Egypt, who planned to recruit a new slave army of black Africans. Although Muḥammad ʿAlī's slave army was a failure, the conquest of the Sudan, and the trade routes opened by Egyptian troops, led to an increase in the numbers of slaves imported to and through Egypt. This trend was amplified by the increased supply of slaves in the aftermath of jihād wars in Central and West Africa at the beginning of the nineteenth century.

In later decades the growing involvement of European powers, mainly Britain, posed a new challenge to slavery and the slave trade. Having just abolished slavery in Europe itself, British diplomats struggled to reduce the number of slaves brought into the United States and the Ottoman Empire in a series of treaties from the 1840s to the 1880s prohibiting slave trade. These efforts culminated in the Anglo-Egyptian convention for the suppression of the slave trade in 1877, and its Anglo-Ottoman parallel in 1880. In 1890 the Ottoman government signed the Brussels Act against the slave trade, and the maritime trade in African slaves gradually abated.

In a parallel development the status of the institution itself was eroded. Although most senior officials, including avowed reformers, still maintained large slave and mamlūk households, later decades of the nineteenth century witnessed a rapid erosion of slavery's legal and moral basis. Laws concerning the legal status of slaves were enacted as part of the changes promised in the Gülhâne rescript of 1839 and the Islâhat Fermanı of 1856. Some of the first decisions by the reformed courts and committees in the Ottoman Empire and Egypt denied slaves the special status of diminished responsibility accorded them by sharīʿah. Other verdicts established the legal equality of slaves. When slave-holding Circassian tribes fleeing the Russians sought refuge in the empire in midcentury, Ottoman courts debated the status of their slaves, and decided to accord them Ottoman citizenship. Other decisions further eroded the sharīʿah basis of slavery by defining it as a specifically Islamic institution, which can therefore be enforced only on those who have decided to embrace Islam. Thus, from an Islamic point of view, slavery ceased to be a purely intrusive institution. The legality of slavery was finally revoked in a decree of 1887, declaring that “The Imperial government not officially recognizing the state of slavery, considers by law every person living in the empire to be free” (George Young, Corps de droit Ottoman, 1905, vol. 2, p. 170).

In spite of these declarations, at the beginning of the twentieth century slavery lived on in the Ottoman Empire and in other parts of the Islamic world. The imperial harem of Abdülhamid II (r. 1876–1909) still contained hundreds of women and eunuchs. Large slave populations continued to exist in Arab lands, in the Indian subcontinent, and in Africa. In most states of the Arabian peninsula slavery was abolished only in the second half of the twentieth century. Since then it is almost extinct in the central lands of Islam but has never entirely disappeared. During the 1980s, as a result of civil wars in Sudan and Somalia, slavery reappeared in these regions. Reports from Sudan reveal that the practice is still widespread in border areas between the northern and southern parts of the country.