Serenus may refer to:
Serenus of Alexandria (died c. 202), Christian martyr and saint in Roman Egypt Serenus Sammonicus (died 212), Roman scholar Serenus of Antinoöpolis (c. 300–c. 360), also known as Serenus of Antinoeia, Greek mathematician in Roman Egypt Serenus the Gardener, also known as Serenus of Sirmium, 4th century martyr, Roman Catholic and Eastern Orthodox saint Serenus, Jewish messiah claimant (c. 720)
See also Serenicus (c. 620–c. 669), Italian Benedictine monk, monastery founder and Catholic saint Serenidus of Saulges (c. 600–c. 680), Italian Benedictine monk and Catholic saint, brother of Serenicus