Maximus of Mainz was an ancient Roman bishop who served as the second leader of the see of Mogontiacum (modern-day Mainz) during the late 4th or early 5th century. He is identified in historical lists as the successor to Aureus. Some historians suggest he may have been the final bishop to hold this office under Roman rule before the Frankish era began. He is recognized as a hieromartyr within the Catholic and Orthodox traditions.