Gaius Licinius Mucianus (fl. 1st century AD) was a general, statesman and writer of ancient Rome. He is considered to have played a role behind the scenes in the elevation of Vespasian to the throne.
His name shows that he had passed by adoption from the gens Mucia to the gens Licinia. Mucianus was sent by Claudius to Armenia with Gnaeus Domitius Corbulo. He was a suffect consul during the reign of Nero, most likely during the years 63 or 64.
At the time of the outbreak of the Jewish revolt in 66 AD, Mucianus was serving as governor of Syria, a post he still held during the Year of Four Emperors (69); however, he failed to put down the Jewish revolt, and Vespasian was sent to replace him. After the death of Galba, Mucianus and Vespasian (who was at the time in Iudaea) both swore allegiance to Otho, but when the civil war broke out, Mucianus persuaded Vespasian to take up arms against Vitellius, who had seized the imperial throne.
It was agreed that Vespasian should stay behind to settle affairs in the East, while Mucianus made his way through Asia Minor and Thrace to attack Vitellius. On his way there, he defeated a Dacian invasion of Moesia. Mucianus reached Rome the day after the death of Vitellius, finding Domitian, Vespasian's son, at head of affairs, but until the arrival of Vespasian the real master of Rome was Mucianus.
Mucianus never wavered in his allegiance to Vespasian, whose favor he retained in spite of his arrogance. He is mentioned in the records of the Arval Brethren in the year 70; Mucianus may have been admitted following Vespasian's entrance to Rome, although Ronald Syme admits that he may have been co-opted in absentia by Galba. He was appointed consul (suffect) for the third time in 72. As no mention is made of Mucianus during the reigns of Titus or Domitian, he probably died during the reign of Vespasian; Syme believes his death happened before 78.