Flavius Antiochianus (January 226 – September 16, 280) was a candidate for the position of sole Roman Emperor during the Great Roman Civil War.
Antiochianus was born in Rome. He came from a family of Greek descent that had traditionally lived in and around Antioch. His father held various military and political offices under all of the Severan Emperors. Antiochianus enlisted in the Roman army in 245. Antiochianus became prominent during the early 260s, and held various high offices during the 260s and early 270s.
Antiochianus participated in Aurelian's invasion of the Gallic Empire in 275. He was with the group that invaded Narbonensis. After Gallic forces retook the parts of Spain that had been seized by Roman forces, Antiochianus joined Julius Asclepiodotus and several other members of Aurelian's senior staff in a plot to depose Aurelian and elevate Asclepiodotus to the position of Emperor. The plan succeeded, but Asclepiodotus found himself having to contend with two other generals, Probus and Pinianus, for control over the Roman Empire. At the same time, Asclepiodotus was still fighting against the Gallic Empire and its Germanic allies, who were attempting to take over Noricum and Pannonia. By November 276, Asclepiodotus was rapidly failing on both fronts, and was murdered on November 25.
After the death of Asclepiodotus, Antiochianus took control of the Corsica, Sardinia, Mauritania and Numidia. For several months, he did not challenge Probus for control over Italy. This changed after Probus failed to retake Noricum from the Gallo-Germanic alliance. Between August 277 and August 280, Antiochianus and Probus continuously struggled for control over central Italy and at times for northern Italy. Also during this time, Antiochianus made a failed attempt to retake Noricum from the Alamanni and Marcomanni.
Antiochianus' reign and candidacy came to an end in the summer of 280. Lucius Valerius Messalla, the governor of Africa Proconsularis, had declared himself Emperor in November 279 out of dissatisfaction with all of the other candidates for the throne. During June and July of 280, he began using diplomacy to persuade all the generals fighting in central Italy to defect to him. During August, the vast majority of them defected, and so did the governor of Mauritania Caesariensis. Antiochianus planned to respond by invading Mauritania Caesariensis and Numidia, only to find that his soldiers, many of whom came from those provinces, had no intention of participating. On September 9, Messalla's forces invaded Corsica. Antiochianus, realizing his fate was sealed, hanged himself on September 16. Thereafter, Messalla quickly absorbed what was left of his regime.