Serenus may refer to:
- Saint Serenus the Gardener (Sirenatus, Cerneuf), also known as Serenus of Sirmium
- Saint Serenus of Alexandria (died 202 AD), Egyptian martyr
- Serenus Sammonicus, a Roman scholar
- Serenus of Antinoöpolis, also known as Serenus of Antinoeia, a mathematician from Antinoöpolis.
- Serenus, a messiah claimant (circa 720)
- Serenicus and Serenidus of Saulges