Olympiodorus the Alchemist was a Greek writer on alchemy active in Alexandria during the 6th century CE. He is a different figure from the well-known philosopher of the same name who wrote commentaries on Plato and Aristotle. Almost nothing is known about his personal life. His work places him in the final era of Alexandria as a major center of learning, a time when alchemy was practiced as a blend of craft, natural philosophy, and mystical thought.

He is credited with an alchemical treatise addressed to a man named Petasius, and a second work titled On the Sacred Art. These surviving texts are technical manuals that also explain the philosophical principles behind transforming materials.

Olympiodorus the Alchemist is a significant source for understanding late antique alchemy. His writings preserve and explain the ideas of earlier practitioners, showing how alchemy was viewed as a sacred art connected to cosmology. According to modern scholars, his work provides a crucial link in transmitting alchemical knowledge from the Greek tradition to later Byzantine and Arabic cultures, documenting the endurance of this technical and philosophical pursuit in the early Christian era.