The history of slavery in the Muslim world began with institutions inherited from pre-Islamic Arabia. The practices of keeping slaves in the Muslim world nevertheless developed in radically different ways in different Muslim states based on a range of social-political factors, as well as the more immediate economic and logistical considerations of the Arab slave trade. As a general principle, Islam encouraged the manumission of Muslim slaves as a way of expiating sins, and many early converts to Islam, such as Bilal, were former slaves. However, Islam never banned the practice, and it persisted as an important institution in the Muslim world through to the modern era.

In classical Islamic law, a concubine was a slave-woman with whom her master engaged in sexual relations. Concubinage was widely accepted by Muslim scholars in pre-modern times. Most modern Muslims, both scholars and laypersons, believe that Islam no longer permits concubinage and that sexual relations are religiously permissible only within marriage.