A Mufti (; Arabic: مفتي) is an Islamic jurist qualified to issue a nonbinding opinion (fatwa) on a point of Islamic law (sharia). The act of issuing fatwas is called iftāʾ. Muftis and their fatwas played an important role throughout Islamic history, taking on new roles in the modern era.

Tracing its origins to the Quran and early Islamic communities, the practice of ifta crystallized with the emergence of the traditional legal theory and schools of Islamic jurisprudence (madhahib). In the classical legal system, fatwas issued by muftis in response to private queries served to inform Muslim populations about Islam, advise courts on difficult points of Islamic law, and elaborate substantive law. In later times, muftis also issued public and political fatwas that took a stand on doctrinal controversies, legitimized government policies or articulated grievances of the population.

Traditionally, a mufti was seen as a scholar of upright character who possessed a thorough knowledge of the Quran, hadith and legal literature. Muftis acted as independent scholars in the classical legal system. Over the centuries, Sunni muftis were gradually incorporated into state bureaucracies, while Shia jurists in Iran progressively asserted an autonomous authority starting from the early modern era.

With the spread of codified state laws and Western-style legal education in the modern Muslim world, muftis generally no longer play their traditional role of clarifying and elaborating the laws applied in courts. However, muftis have continued to advise the general public on other aspects of sharia, particularly questions regarding religious rituals and everyday life. Some modern muftis are appointed by the state to issue fatwas, while others serve on advisory religious councils. Still others issue fatwas in response to private queries on television or over the internet. Modern public fatwas have addressed and sometimes sparked controversies in the Muslim world and beyond.

The legal methodology of modern ifta often diverges from pre-modern practice. While the proliferation of contemporary fatwas attests to the importance of Islamic authenticity to many Muslims, little research has been done to determine to what extent the Muslim public continues to acknowledge the religious authority of muftis or heeds their advice.