Jaʿfar ibn Muḥammad al-Ṣādiq, commonly known as Ja'far al-Ṣādiq, was an 8th-century Muslim scholar. He was the 6th Imam and founder of the Ja'fari school of jurisprudence according to Twelver and Isma'ili Shi'ites. He is also important to Sunnis as a teacher to the Sunni scholars Abu Hanifah and Malik ibn Anas and as a transmitter of Sunni hadith. Ja'far al-Sadiq also figures prominently in the initiatic chains of many Sufi orders.
Despite the fact that a wide range of works in religious as well as scientific disciplines were attributed to him, no works penned by Ja'far himself remain extant.
Al-Sadiq was born around 700, perhaps in 702 CE. He inherited the position of imam from his father in his mid-thirties. As a Shi’a Imam, al-Sadiq stayed out of the political conflicts that embroiled the region, evading the many requests for support that he received from rebels. He was the victim of some harassment by the Abbasid caliphs, and was eventually, according to Shi’a Muslims, poisoned at the orders of the Caliph Al-Mansur. In addition to his connection with Sunni schools of Sunni jurisprudence, he was a significant figure in the formulation of Shia doctrine.