The Battle of the Blacks or Battle of the Slaves was a conflict in Cairo, on 21–23 August 1169, between the black African units of the Fatimid army and other pro-Fatimid elements, and Sunni Syrian troops loyal to the Fatimid vizier, Saladin. Saladin's rise to the vizierate, and his sidelining of the Fatimid caliph, al-Adid, antagonized the traditional Fatimid elites, including the army regiments, as Saladin relied chiefly on the Kurdish and Turkish cavalry troops that had come with him from Syria.

According to the medieval sources, which are biased towards Saladin, this conflict led to an attempt by the palace majordomo, Mu'tamin al-Khilafa, to enter into an agreement with the Crusaders and jointly attack Saladin's forces in order to get rid of him. Saladin learned of this conspiracy, and had Mu'tamin executed on 20 August. Modern historians have questioned the veracity of this report, suspecting that it may have been invented to justify Saladin's subsequent move against the Fatimid troops.

This event provoked the uprising of the black African troops of the Fatimid army, numbering some 50,000 men, who were joined by Armenian soldiers and the populace of Cairo the next day. The clashes lasted for two days, as the Fatimid troops initially attacked the Vizier's palace, but were driven back to the large square between the Fatimid Great Palaces. There the black African troops and their allies appeared to be gaining the upper hand, until al-Adid came out publicly against them, and Saladin ordered the burning of their settlements, located south of Cairo outside the city wall, where the black Africans' families had been left behind. The black Africans then broke and retreated in disorder to the south, until they were encircled near the Bab Zuwayla gate, where they surrendered and were allowed to cross the Nile to Giza. Despite promises of safety, they were attacked and almost annihilated there by Saladin's brother Turan-Shah.