Abu Nasr Muhammad al-Farabi (Arabic: أبو نصر محمد الفارابي, romanized: Abū Naṣr Muḥammad al-Fārābī; c. 870 – 14 December 950–12 January 951), known in the Latin West as Alpharabius, was an early Islamic philosopher and music theorist. He has been designated as "Father of Islamic Neoplatonism", and the "Founder of Islamic Political Philosophy".

Al-Farabi's fields of philosophical interest included—but not limited to, philosophy of society and religion; philosophy of language and logic; psychology and epistemology; metaphysics, political philosophy, and ethics. He was an expert in both practical musicianship and music theory, and although he was not intrinsically a scientist, his works incorporate astronomy, mathematics, cosmology, and physics.

Al-Farabi is credited as the first Muslim who presented philosophy as a coherent system in the Islamic world, and created a philosophical system of his own, which developed a philosophical system that went far beyond the scholastic interests of his Greco-Roman Neoplatonism and Syriac Aristotelian precursors. That he was more than a pioneer in Islamic philosophy, can be deduced from the habit of later writers calling him the "Second Master", with Aristotle as the first.

Al-Farabi's impact on philosophy is undeniable, to name a few, Yahya ibn Adi, Abu Sulayman Sijistani, Abu al-Hassan al-Amiri, and Abu Hayyan al-Tawhidi; Avicenna, Suhrawardi, and Mulla Sadra; Avempace, Ibn Tufail, and Averroes; Maimonides, Albertus Magnus, and Leo Strauss. He was known in the Latin West, as well as the Islamic world.

The existing variations in the basic accounts of al-Farabi's origins and pedigree indicate that they were not recorded during his lifetime or soon thereafter by anyone with concrete information, but were based on hearsay or guesses (as is the case with other contemporaries of al-Farabi). Little is known about his life. Early sources include an autobiographical passage where al-Farabi traces the history of logic and philosophy up to his time, and brief mentions by al-Masudi, Ibn al-Nadim and Ibn Hawqal. Said al-Andalusi wrote a biography of al-Farabi. Arabic biographers of the 12th–13th centuries thus had few facts to hand, and used invented stories about his life.

From incidental accounts it is known that he spent significant time (most of his scholarly life) in Baghdad with Syriac Christian scholars, including the cleric Yuhanna ibn Haylan, Yahya ibn Adi, and Abu Ishaq Ibrahim al-Baghdadi. He later spent time in Damascus and in Egypt before returning to Damascus where he died in 950–951.

His name was Abu Nasr Muhammad ibn Muhammad al-Farabi, sometimes with the family surname al-Tarkhani, i.e., the element Tarkhan appears in a nisba. His grandfather was not known among his contemporaries, but a name Awzalagh, in Arabic, suddenly appears later in the writings of Ibn Abi Usaybi'a, and of his great-grandfather in those of Ibn Khallikan.

His birthplace could have been any one of the many places in Central Asia—then known by the name of Khurasan. The word farab is a Persian term for a locale that is irrigated by effluent springs or flows from a nearby river. Thus, there are many places that carry the name (or various evolutions of that toponym) in that general area, such as Farab (Otrar) on the Jaxartes (Syr Darya) in modern Kazakhstan; Farab, an still-extant village in suburbs of the city of Chaharjuy/Amul (modern Türkmenabat) on the Oxus Amu Darya in Turkmenistan, on the Silk Road, connecting Merv to Bukhara, or Faryab in Greater Khorasan (modern day Afghanistan). The older Persian Parab (in Hudud ul-'alam) or Faryab (also Paryab), is a common Persian toponym meaning "lands irrigated by diversion of river water".