John Philoponus was a Christian philosopher, theologian, and scholar active in Alexandria during the 6th century CE. His nickname, "Philoponus," meaning "lover of toil," likely refers to his scholarly diligence. He studied under the Neoplatonist teacher Ammonius Hermiae, and his early career produced detailed commentaries on the works of Aristotle. Later, he became a committed Christian theologian, engaging in complex doctrinal debates of his time. His career bridges late antique Greek philosophy and early Christian intellectual culture.

His writings are broadly divided into philosophical and theological works. Major surviving texts include his extensive commentaries on Aristotle and two important treatises arguing against the idea of an eternal universe: Against Proclus on the Eternity of the World and On the Creation of the World. His theological work, the Arbiter, which argued for a specific Christological position, survives in Syriac translation.

John Philoponus is historically significant for his critical and innovative engagement with Aristotelian science. According to modern scholars, he proposed an early theory of "impetus" to explain projectile motion, which anticipated later medieval physics. He also forcefully argued against Aristotle's doctrine of the eternity of the world, a critique that became highly influential in later Islamic and Latin philosophical traditions. Although his unorthodox theological views led to his official condemnation as a heretic decades after his death, his philosophical works continued to be studied for centuries. Academics view him as a pivotal figure in the transition from ancient to medieval thought.