Regalianus (died 260) had been made general by emperor Valerian and like many others of his rank he was proclaimed Roman emperor in 260 after the capture and execution of Valerian by Shapur I of Persia. He was a senator and general in command of Illyricum, and was married to Sulpicia Dryantilla .

About his origin, the Tyranni Triginta says he was a Dacian, a kinsman of Decebalus.

There is some evidence that he was involved in the revolt of Ingenuus but others see him acting independently. His power was centered at Carnuntum, a garrison town on the upper Danube and coins have been found bearing his name.

After the defeat of Ingenuus by Roman emperor Gallienus, Regalianus' supporters panicked and killed him.

A few anecdotes survive about this man, in the brief biographical sketch of him given in the Book on Thirty Tyrants in the Historia Augusta: it is stated for example that he was raised to the throne because of his name (Rex, Regis, Regi, Regalianus); when his soldiers heard this jest they greeted Regalianus as their emperor.