Aristotelianism ( /ˌærɨstəˈtiːliənɨzəm/ ARR-i-stə-TEE-li-ə-niz-əm) is a tradition of philosophy that takes its defining inspiration from the work of Aristotle. The works of Aristotle were initially defended by the members of the Peripatetic school, and, later on, by the Neoplatonists, who produced many commentaries on Aristotle's writings. In the Islamic world, the works of Aristotle were translated into Arabic, and under philosophers such as Al-Kindi, Al-Farabi, Avicenna, and Averroes, Aristotelianism became a major part of early Islamic philosophy. Although some knowledge of Aristotle's logical works was known to western Europe, it wasn't until the Latin translations of the 12th century that the works of Aristotle and his Arabic commentators became widely available. Scholars such as Albertus Magnus and Thomas Aquinas interpreted and systematized Aristotle's works in accordance with Christian theology.

The original followers of Aristotle were the members of the Peripatetic school. The most prominent members of the school after Aristotle were Theophrastus and Strato of Lampsacus, who both continued Aristotle's researches. During the Roman era the school concentrated on preserving and defending his work. The most important figure in this regard was Alexander of Aphrodisias who commentated on Aristotle's writings. With the rise of Neoplatonism in the 3rd century, Peripateticism as an independent philosophy came to an end, but the Neoplatonists sought to incorporate Aristotle's philosophy within their own system, and produced many commentaries on Aristotle.