A madhhab (Arabic: مَذْهَب, romanized: madhhab, lit. 'way to act', IPA: [ˈmaðhab], pl. مَذَاهِب, madhāhib, [ˈmaðaːhib]) refers to any school of thought within Islamic jurisprudence. The major Sunni madhhab are Hanafi, Maliki, Shafi'i and Hanbali. They emerged in the ninth and tenth centuries CE and by the twelfth century almost all Islamic jurists aligned themselves with a particular madhhab. These four schools recognize each other's validity and they have interacted in legal debate over the centuries. Rulings of these schools are followed across the Muslim world without exclusive regional restrictions, but they each came to dominate in different parts of the world. For example, the Maliki school is predominant in North and West Africa; the Hanafi school in South and Central Asia; the Shafi'i school in East Africa and Southeast Asia; and the Hanbali school in North and Central Arabia. The first centuries of Islam also witnessed a number of short-lived Sunni madhhabs. The Zahiri school, which is considered to be endangered, continues to exert influence over legal thought. The development of Shia legal schools occurred along the lines of theological differences and resulted in the formation of the Ja'fari madhhab amongst Twelver Shias, as well as the Isma'ili and Zaydi madhhabs amongst Isma'ilis and Zaydis respectively, whose differences from Sunni legal schools are roughly of the same order as the differences among Sunni schools. The Ibadi legal school, distinct from Sunni and Shia madhhabs, is predominant in Oman. Unlike Sunnis, Shias, and Ibadis, non-denominational Muslims are not affiliated with any madhhab.
The transformations of Islamic legal institutions in the modern era have had profound implications for the madhhab system. With the spread of codified state laws in the Muslim world, the influence of the madhhabs beyond personal ritual practice depends on the status accorded to them within the national legal system. State law codification commonly drew on rulings from multiple madhhabs, and legal professionals trained in modern law schools have largely replaced traditional ulama as interpreters of the resulting laws. In the 20th century, some jurists began to assert their intellectual independence from traditional madhhabs. With the spread of Salafi influence and reformist currents in the 20th century; a handful of Salafi scholars have asserted independence from being strictly bound by the traditional legal mechanisms of the four schools. Nevertheless, the majority of Sunni scholarship continues to uphold post-classical creedal belief in rigorously adhering (Taqlid) to one of the four schools in all legal details.
