Lucius Tettius Julianus, in some passages of Tacitus is called "Titius", in others "Tertius", but Tettius is probably the correct form. He was the commander of one of the three legions stationed in Moesia under Marcus Aponius Saturninus, and along with his fellow-commanders received the consular insignia from Otho, in consequence of a victory which they gained over the Rhoxolani, a Sarmatian tribe.
Shortly afterwards, Aponius Saturninus made an attempt upon the life of Tettius, apparently because of an old grudge. Tettius escaped across Mount Haemus. He took no part in the civil war during the Year of the Four Emperors, although the legion, which he commanded, espoused the cause of Vespasian, and pleaded various delays which prevented him from joining his troops. On the triumph of the party of Vespasian, he was, notwithstanding, appointed one of the praetors; but the Roman senate would not allow him to enter upon the dignity, and conferred his office upon Plotius Griphus, on 1 January 70. Domitian, however, almost immediately afterwards, restored him to the praetorship.