Unani-tibb or Unani Medicine also spelled Yunani Medicine ( /juːˈnɑːni/; Yūnānī in Arabic, Hindi-Urdu and Persian) means "Greek Medicine", and is a form of traditional medicine widely practiced in South Asia. It refers to a tradition of Graeco-Arabic medicine, which is based on the teachings of Greek physician Hippocrates, and Roman physician Galen, and developed into an elaborate medical System by Arab and Persian physicians, such as Rhazes, Avicenna (Ibn Sena), Al-Zahrawi, and Ibn Nafis.

Unani medicine is based on the concept of the four humours: Phlegm (Balgham), Blood (Dam), Yellow bile (Ṣafrā') and Black bile (Saudā').

The word Unani or Yunani has its origins in the Greek word Ἰωνία (Iōnía) or Ἰωνίη (Iōníe), a place name given to a Greek populated coastal region of Anatolia.

Though the threads which comprise Unani healing can be traced all the way back to Claudius Galenus of Pergamum, who lived in the second century of the Christian Era and also to Ancient Iranian Medicine, the basic knowledge of Unani medicine as a healing system was developed by Hakim Ibn Sina (known as Avicenna in the west) in his medical encyclopedia The Canon of Medicine. The time of origin is thus dated at circa 1025 AD, when Avicenna wrote The Canon of Medicine in Persia. While he was primarily influenced by Greek and Islamic medicine, he was also influenced by the Indian medical teachings of Sushruta and Charaka.