Fiqh (; Arabic: فقه [fɪqh]) is Islamic jurisprudence. Fiqh is often described as the human understanding and practices of the sharia, that is human understanding of the divine Islamic law as revealed in the Quran and the Sunnah (the teachings and practices of the Islamic prophet Muhammad and his companions). Fiqh expands and develops Shariah through interpretation (ijtihad) of the Quran and Sunnah by Islamic jurists (ulama) and is implemented by the rulings (fatwa) of jurists on questions presented to them. Thus, whereas sharia is considered immutable and infallible by Muslims, fiqh is considered fallible and changeable. Fiqh deals with the observance of rituals, morals and social legislation in Islam as well as economic and political system. In the modern era, there are four prominent schools (madh'hab) of fiqh within Sunni practice, plus two (or three) within Shi'a practice. A person trained in fiqh is known as a faqīh (plural fuqaha).

Figuratively, fiqh means knowledge about Islamic legal rulings from their sources. Deriving religious rulings from their sources requires the mujtahid (an individual who exercises ijtihad) to have a deep understanding in the different discussions of jurisprudence. A faqīh must look deep down into a matter and not content himself with just the apparent meaning, and a person who only knows the appearance of a matter is not qualified as a faqīh.

The studies of fiqh, are traditionally divided into Uṣūl al-fiqh (principles of Islamic jurisprudence, lit. the roots of fiqh, alternatively transliterated as Usool al-fiqh), the methods of legal interpretation and analysis; and Furūʿ al-fiqh (lit. the branches of fiqh), the elaboration of rulings on the basis of these principles. Furūʿ al-fiqh is the product of the application of Uṣūl al-fiqh and the total product of human efforts at understanding the divine will. A hukm (plural aḥkām) is a particular ruling in a given case.