Pappus the Alchemist was a writer active in the Greco-Egyptian world during late antiquity. His precise dates and personal history are unknown, but scholars place his life somewhere between the 2nd and 4th centuries CE based on the style of his work. He is not the same person as the mathematician Pappus of Alexandria. His role was that of a practitioner and writer within the ancient tradition of alchemy.

He is known for a single, fragmentary treatise titled On the Making of Gold and Silver. This text is a practical and philosophical guide to metallic transmutation, focusing on processes to create gold and silver. It survives because it was copied and preserved in Byzantine manuscripts centuries later, collected alongside works by other famous alchemists.

According to modern scholars, Pappus’s significance lies in his text being a direct witness to the technical practices and symbolic language of late antique alchemy. His work represents an important strand of early "scientific" literature, contributing to our understanding of how chemical processes and philosophical ideas were intertwined in the ancient Mediterranean world.