Hundreds of years before habitus became a full-fledged sociological concept in the modern West, the polymath Ibn Khaldun (d. 808/1406), a champion of nurture over nature, demonstrated brilliantly how indispensable the acquisition of a suitable habitus was for successful functioning of humans in their social environment. Ibn Khaldun goes so far as to argue that acquired dispositions replace humans’ natural dispositions to make them who they are, in both thought and behavior. He shows how to become knowledgeable or skilled in whatever field, craft, competence, or language requires the acquisition of a suitable habitus. The old and perennial question of ‘nature versus nurture’, or the balance between nature and environment in the human character, has been questioned ceaselessly since antiquity. The habitus concept, originally used by Aristotle (in Greek: hexis), has played an important role throughout its long history in discussions probing this question. The concept, especially for its role in Pierre Bourdieu’s theory of practice, has gained considerable currency in the social sciences and humanities since the 1970’s. Yet, it is hardly known that through the translation of Greek texts, habitus, malaka and hay`a in Arabic, was appropriated and naturalized by thinkers in the medieval Islamic world. In fact, the concept was developed and integrated in various intellectual systems and environments since its introduction to the Islamic world in the 3rd/9th century. As other concepts, habitus crossed religious boundaries to be used in medieval Hebrew works as qinyan. This paper focuses on the habitus concept as it was known and used in the Islamic world. It discusses important landmarks in its development starting in the 3rd/9th century and ending in the 19th century, with an emphasis on its employment by al-Farabi, Miskawayh, Avicenna, Ibn Khaldun, and Muhammad ?Abduh. One of the interesting findings of this paper is that in the Islamic tradition of habitus, unlike the Western tradition until the early 20th century, the concept has been applied to analyze social and cultural phenomena. In other words, the concept was not limited to abstract philosophical discourse, but served as a sociological analytic tool by philosophically-informed scholars to make observations on their society.