Archelaus the Alchemist was a Greek writer active sometime in late antiquity, with scholarly estimates placing his life between the 3rd and 6th centuries CE. He is known only as the author of a single surviving work, a didactic poem titled On the Sacred Art. No biographical details about his origin or life are recorded.

His work belongs to the tradition of Greco-Egyptian alchemy, a field that blended practical laboratory techniques with philosophical speculation. Archelaus’s primary significance lies in his use of poetry to convey this technical knowledge. By composing his instructions in Greek hexameter verse, he followed an established tradition of presenting specialized subjects in a memorable, elevated form. According to modern scholars, this choice highlights how practitioners sought to present alchemy not just as a craft, but as a "sacred art" worthy of literary treatment. Within the larger body of Greek alchemical writings, which is largely in prose, his verse composition provides important evidence for the literary and cultural dimensions of this esoteric field.