| Religion: | Islam |
| Era: | Islamic golden age |
| Abu'l-Husayn al-Basri | |
| Death Date: | 436 H (1044 CE) |
| Maddhab: | Hanafi[1] [2] |
| School Tradition: | Mu'tazila |
| Occupation: | Scholar of Islam |
| Main Interests: | Usul |
| Influences: | Wasil ibn Ata, Abu al-Hudhayl al-'Allaf |
| Influenced: | Ibn al-Malāḥimī |
| Works: | al-Mu'tamad fi Usul al-Fiqh |
Abu'l-Husayn al-Basri (died 436/1044) was a Mu'tazilite jurist and theologian. He wrote al-Mu'tamad fi Usul al-Fiqh (The Canon of the Foundations of Jurisprudence), a major source of influence in informing the foundations of Islamic jurisprudence until Fakhr al-Din al-Razi's al-Mahsul fi 'Ilm al-Usul (The Compilation of the Fundamentals of the Legal Sciences).
He was a physician as well as a disciple of the Mu'tazilite judge Abd al-Jabbar in Rey. He challenged some of his master's teachings and eventually compiled a huge (two volumes; 1500 pages) critical review of the arguments and proofs used in Islamic scholastic theology. This, he summarised in al-Mu'tamad and included a critique of the qualifications of a legist. His works were generally handed down among students of medicine, and it was a century before his teachings were revived and espoused by the Mu'tazili scholar Ibn al-Malahimi in Khorezm in Central Asia, where they gained recognition as a school of Mu'tazili theology.