Quintus Baienus Blassianus was a Roman eques who held a number of military and civilian positions during the reign of the Emperors Antoninus Pius and Marcus Aurelius, including praefectus of the Classis Britannica, and of Roman Egypt.
Blassianus' home, based on the presence of a number of inscriptions, is believed to be Trieste. Based on his filiation, attested in at least one inscription, indicates his father's praenomen was Publius, and his tribe was Pupinia.