Marcian most often refers to Flavius Marcianus, Eastern Roman emperor from 450 to 457 AD
Marcian (Marcianus) may also refer to:
- Marcian of Syracuse (first bishop of Syracuse)
- Saint Marcian of Tortona (died 120 AD)
- Marcion of Sinope, 2nd century AD Christian heretic
- Marcian of Rhossos (fl. 2nd century), alleged author of the Gospel of Peter, may be the same as Marcion of Sinope
- Aelius Marcianus, 3rd century AD jurist
- Lucius Aurelius Marcianus, 3rd century AD Roman soldier
- Marcian of Heraclea, 4th century AD geographer
- Marcianus (praefectus urbi), an urban prefect of Rome in 409 AD
- Marcian (usurper), tried to overthrow Emperor Zeno in 479 AD
- Marcian (cousin of Justin II), Byzantine general and cousin of Justin II
- Marziano Lavarello ("Marziano II" or "Marcianus II"), 20th century AD Italian eccentric and pretender