The House of Wisdom (Arabic: بَيْت الْحِكْمَة Bayt al-Ḥikmah), also known as the Grand Library of Baghdad, was believed to be a major Abbasid-era public academy and intellectual center in Baghdad. In popular reference, it acted as one of the world's largest public libraries during the Islamic Golden Age, and was founded either as a library for the collections of the fifth Abbasid caliph Harun al-Rashid (r. 786–809) in the late 8th century or as a private collection of the second Abbasid caliph al-Mansur (r. 754–775) to house rare books and collections in the Arabic language. During the reign of the seventh Abbasid caliph al-Ma'mun (r. 813 – 833 AD), it was turned into a public academy and a library.

It was destroyed in 1258 during the Mongol siege of Baghdad. The primary sources behind the House of Wisdom narrative date between the late eight centuries and thirteenth centuries, and most importantly include the references in Ibn al-Nadim's (d. 995) al-Fihrist.

More recently, the narrative of the Abbasid House of Wisdom acting as a major intellectual center, university, and playing a sizable role during the translation movement has been understood by some historians to be a myth, constructed originally over the course of the nineteenth and early twentieth centuries by Orientalists and, through their works, propagated its way into scholarship and nationally-oriented works until more recent re-investigations of the evidence.

The House of Wisdom existed as a part of the major Translation Movement taking place during the Abbasid Era, translating works from Greek and Syriac to Arabic, but it is unlikely that the House of Wisdom existed as the sole center of such work, as major translation efforts arose in Cairo and Damascus even earlier than the proposed establishment of the House of Wisdom. This translation movement lent momentum to a great deal of original research occurring in the Muslim world, which had access to texts from Greek, Persian, and Indian sources. The rise of advanced research into mathematics, astronomy, philosophy, and medicine was the beginning of Arabic science, and drove demand for more and updated translations.

The House of Wisdom was made possible by the consistent flow of Arab, Persian, and other scholars of the Islamic world to Baghdad, owing to the city's position as capital of the Abbasid Caliphate. This is evidenced by the large number of scholars known to have studied in Baghdad between the 8th and 13th centuries, such as al-Jahiz, al-Kindi, and al-Ghazali among others, all of whom would have contributed to a vibrant academic community in Baghdad, producing a great number of notable works, regardless of the existence of a formal academy. The fields to which scholars associated with the House of Wisdom contributed include, but are not limited to, philosophy, mathematics, medicine, astronomy, and optics. The early name of the library, Khizanat al-Hikma (literally, "Storehouse of Wisdom"), derives from its function as a place for the preservation of rare books and poetry, a primary function of the House of Wisdom until its destruction. Inside the House of Wisdom, writers, translators, authors, scientists, scribes, and others would meet daily for translation, writing, conversation, reading, and dialogue. Numerous books and documents covering several scientific concepts and philosophical subjects in different languages were translated in this house.

Throughout the 4th to 7th centuries, scholarly work in the Arabic languages was either newly initiated or carried on from the Hellenistic period. Centers of learning and of transmission of classical wisdom included colleges such as the School of Nisibis and later the School of Edessa, and the renowned hospital and medical Academy of Gondishapur; libraries included the Library of Alexandria and the Imperial Library of Constantinople; and other centers of translation and learning functioned at Merv, Salonika, Nishapur and Ctesiphon, situated just south of what was later to become Baghdad.

During the Umayyad era, Muawiyah I started to gather a collection of books in Damascus. He then formed a library that was referred to as "Bayt al-Hikma". Books written in Greek, Latin, and Persian in the fields of medicine, alchemy, physics, mathematics, astrology and other disciplines were also collected and translated by Muslim scholars at that time. The Umayyads also appropriated paper-making techniques from the Chinese and joined many ancient intellectual centers under their rule, and employed Christian and Persian scholars to both translate works into Arabic and to develop new knowledge. These were fundamental elements that contributed directly to the flourishing of scholarship in the Arab world.

In 750, the Abbasid dynasty replaced the Umayyad as the ruling dynasty of the Islamic Empire, and, in 762, the Caliph al-Mansur (r. 754–775) built Baghdad and made it his capital instead of Damascus. Baghdad's location and cosmopolitan population made the perfect location for a stable commercial and intellectual center. The Abbasid dynasty had a strong Persian bent, and adopted many practices from the Sasanian Empire—among those, that of translating foreign works, except that now texts were translated into Arabic. For this purpose, al-Mansur founded a palace library modeled after the Sasanian Imperial Library, and provided economic and political support to the intellectuals working there. He also invited delegations of scholars from India and other places to share their knowledge of mathematics and astronomy with the new Abbasid court.