Melanius may refer to:
Saint Melaine, also spelled Melanius, 6th century bishop of Rennes Saint Melanius I of Viviers, 5th century bishop of the Roman Catholic Diocese of Viviers Saint Melanius II of Viviers, 6th century bishop of the Roman Catholic Diocese of Viviers
See also Saint Mellonius (229–314), possibly fictitious bishop of Rotomagus