priestly family of Iranian origin, from the city of Balkh in Khorāsān, who achieved prominence in the 8th century as scribes and viziers to the early ʿAbbāsid (Abbāsid Dynastyʿ) caliphs. Their ancestor was a barmak, a title borne by the high priest in the Buddhist temple of Nawbahār. The Barmakids were also known for their patronage of literature, philosophy, and science and for their tolerant attitude toward various religious and philosophical issues. They promoted public works—such as canals, mosques, and postal services—but also squandered money on building magnificent palaces by the Tigris.

When Balkh, the native town of the Barmakids, fell to the Arabs c. 663, Khālid ibn Barmak and his brothers moved to the garrison city of Basra in Iraq, where they converted to Islām.

Khālid ibn Barmak is the first Barmakid about whom much is known. He first appears in the mid-8th century as a supporter of the revolutionary movement that established the ʿAbbāsid caliphate. In 747 Khālid was put in charge of the distribution of spoils when the ʿAbbāsid army moved toward Iraq. Afterward, he was sent to Dayr Qunnā to administer the district. Under the ʿAbbāsid caliph Abū al-ʿAbbās as (Abū al-ʿAbbās as-Saffāḥ) Saffāḥ, Khālid shared ministerial authority with Abū al-Jahm and was entrusted with the army and the collecting of the land tax.

Khālid's intimacy with the Caliph reached the extent that the latter entrusted him with the upbringing of his daughter. During the reign of al-Manṣūr (Manṣūr, al-), Khālid was appointed governor of Fars, and in 765 he was among the delegates to obtain Prince ʿIsā's renunciation of succession to the caliphate. Khālid then was nominated governor of Ṭabaristān, where coins were struck in his name between 767 and 771. There, he distinguished himself by capturing Ustūnā Wand and building a town called Manṣūrah. Because of political intrigues and rivalry, al-Manṣūr dismissed Khālid in 775 and imposed a heavy fine upon him. Al-Khayzurān, Prince al-Mahdī's wife, helped him to raise the money. Subsequently Khālid was sent to Mosul to suppress Kurdish disturbances while his son Yaḥyā was put in charge of Azerbaijan. The Barmakids were endowed with more privileges during al-Mahdī's reign, when Khālid, helped by his son Yaḥyā, was appointed governor of Fars.

Khālid died in 781/782. Yaḥyā, well trained by his father and already undertaking various administrative jobs, was nominated in 778 as secretary-tutor to the Caliph's son Hārūn (Hārūn ar-Rashīd). As secretary, he played a decisive role in ensuring the succession of his ward to the caliphate. In 779/780 the Caliph appointed Hārūn, accompanied by Yaḥyā, to lead the expedition against the Byzantines. On his return Hārūn was put in charge of the western provinces, with Yaḥyā as his adviser. In 781 Hārūn was proclaimed second in succession after his brother Mūsā, but a little later—and due to al-Khayzurān's and Yaḥyā's influence—the Caliph intended to deprive Mūsā of his rights as an heir apparent but died before accomplishing his scheme. Hārūn decided not to put up any opposition to the new caliph Mūsā al-Hādī. This wise decision, inspired by Yaḥyā, perhaps saved the empire from civil war.

Al-Hādī, in turn, confirmed Yaḥyā's position with Hārūn. This was, no doubt, a tactical error by al-Hādī, for when he decided to nominate his own son to the caliphate, Hārūn would have given in had Yaḥyā not objected. Yaḥyā tried in vain to convince the Caliph that the violation of an oath after so short a time would have disastrous consequences. Hārūn and Yaḥyā were jailed. At this point, however, al-Hādī suddenly died in obscure circumstances.

Thus Hārūn ar-Rashīd (786–809) was raised to power not by his own efforts but by the machinations of the queen mother al-Khayzurān and Yaḥyā the Barmakid. It was, therefore, no surprise that he put the whole administration in the hands of Yaḥyā and his sons. Yaḥyā received the title of wazīr, and his sons al-Faḍl and Jaʿfar were placed in charge of the Caliph's personal seal.

Al-Faḍl and Jaʿfar also bore the title wazīr. Jaʿfar, the younger brother and ar-Rashīd's favourite, was known for his eloquence and for his love of pleasure and parties. He rarely left the court, but when, in 796, the Caliph sent him to control a disturbance in Syria, Jaʿfar succeeded in quieting the situation. On his return, he was appointed director of the bureaus (dīwāns) of the post, textiles, and mint. In the latter office Jaʿfar minted coins in his name in various provinces. Al-Faḍl, unlike his brother, distinguished himself by his competence and seriousness. When in 792 the ʿAlid Yaḥyā ibn ʿAbd Allāh rebelled in Daylam, al-Faḍl, through diplomacy and promises, persuaded him to give in. In 793 al-Faḍl was appointed governor of Khorāsān; he was able to put an end to the disturbances in Kābul. In 797 al-Faḍl took over the central government from his father, who resided at Mecca. Al-Faḍl, besides, was a tutor to ar-Rashīd's elder son and heir apparent, al-Amīn.

The Barmakids' influence lasted 17 years, but they were extirpated at the peak of their power and fortune. Jaʿfar, only 36 years old, was executed in 803 and parts of his body displayed on the bridges of Baghdad. Other Barmakids, with the exception of Muḥammad ibn Khālid, were imprisoned and their property confiscated. Yaḥyā and al-Faḍl died in prison in 805 and 808, respectively. A number of their partisans were accused of heresy and executed.

The Barmakids' fall was sudden and brutal. Many accusations were made against them at the time, but the Barmakids' disgrace is to be attributed, first, to their overmighty influence in the court, administration, and society. Second, they seized every opportunity to enrich themselves (which accounts for their ostentatious generosity). Thirdly, they showed a certain degree of liberalism toward various religious and political sects, which the Caliph considered as a danger to his authority. The Barmakids' role ended but their fame survived. They became the subject of controversies among historians. Contradictory traditions, marred by the obvious flattery or prejudice by which they are inspired, represent an attempt by narrators to exalt or discredit the Barmakids' character, thus obscuring their true historical role. Late Muslim literature, especially Persian literature, is inclined to visualize the Barmakid period as an ideal period in the history of the caliphate. These traditions even consider the Barmakids Zoroastrian by faith and trace their descent to the Sāsānid period. Be that as it may, their downfall was to be considered the end of the theory that ministers were initiators of policy and not merely heads of administration; it also marked the Caliph's reaction against the liberal tendency current at the time.

The expression Barmecide feast, for an imaginary banquet, comes from “The Barber's Tale of His Sixth Brother” (The Arabian Nights' Entertainment), where a Barmakid has a series of empty dishes served to a hungry man to test his sense of humour.