Al-Malik Az-Zahir Sayf ad-Din Barquq (Arabic: الملك الظاهر سيف الدين برقوق; born c. 1336) was the first Sultan of the Circassian Mamluk Burji dynasty of Egypt ruling from 1382 to 1389 and 1390 to 1399. Born to a Christian father in Circassia, Barquq was enslaved and later arrived in Egypt. He deposed sultan al-Salih Hajji to claim the throne for himself. Once in power, he placed many of his family members in positions of power. Rebelling governors in 1389 restored Hajji to the throne but Barquq was able to reclaim the throne shortly after and ruled until his death in 1399 and was succeeded by his son. The name Barquq is of Circassian origin and is his birth name.

Barquq was of Circassian origin, and was acquired as a slave, presumably after a battle, and sold to a bathhouse in Crimea. According to one narration, while trying to escape and secretly go to Constantinople, he was attacked by Bulgarian bandits and sold to Egypt, while according to another narration he was directly brought from Crimea to Egypt. In Egypt, he became a mamluk in the household of Yalbugha al-Umari in approximately 1363–64 (or 764 on the Islamic calendar). During the reign of Sultan al-Mansur Ali, when Barquq held considerable influence in the Mamluk state, he brought his father to Egypt in March 1381. His father, originally a Christian, converted to Islam, adopted the name Anas and became the first father of a first-generation mamluk to be mentioned by the Mamluk era sources because of his Muslim faith; the fathers of first generation mamluks were typically non-Muslims. Anas was promoted to the rank of emir of one hundred (the highest Mamluk military rank) and was known for his piety, kindness and charitable acts. He died ten months after his arrival to Egypt.

Since 1341, the Mamluk empire had been ruled by the descendants of al-Nasir Muhammad. However, none of them were strong enough to exert effective control. Many of the rulers were minors at the time of their accession, and would act as puppets for one or another competing Mamluk faction.

This happened in 1377, when the sultan al-Ashraf Sha'ban, who had ruled in his own stead since 1366, was overthrown and killed. The rebelling Mamluks replaced him on the throne with his seven-year-old son. When that puppet sultan died, he was replaced by the younger brother, al-Salih Hajji.

Barquq was a member of the faction behind the throne, serving in various powerful capacities in the court of the boy sultans. He consolidated his power until in November 1382 when he was able to depose sultan al-Salih Hajji and claim the sultanate for himself. He took the reign name al-Zahir, perhaps in imitation of the sultan al-Zahir Baybars.

Barquq placed many of his own family in positions of power to the detriment of fellow Mamluks, attempting to solidify his position. He sponsored the construction of the Mosque-Madrasa of Sultan Barquq in the center of Cairo. Completed in 1386, it was a pious foundation designed to serve as both a khanqah and a madrasa. It is one of the three dominant Islamic monuments clustered on the street Bayn al-Qasrayn in Fatimid Cairo. Although often called the Mausoleum of Barquq, only his daughter is buried there.

Barquq ended the public holiday in Egypt celebrating the Coptic New Year Nayrouz.

The central caravanserai of the famous Cairo souk Khan El-Khalili was founded in the first year of his first reign, though it was founded by his emir, Djaharks el-Khalili.