Gaius Julius Cornutus Tertullus was a Roman senator who was active during the late 1st and early 2nd centuries. He is best known as the older friend of Pliny the Younger, with whom Cornutus was suffect consul for the nundinium of September-October 100.
How Cornutus is related to other known Romans of his time is unclear. Older authorities note that the one inscription that preserves his full name is missing the middle of the relevant line, and conclude from the name of his son, Gaius Julius Plancius Varius Cornutus, Cornutus' full name may be Gaius Julius Plancius Varius Cornutus Tertullus. This would imply that he is somehow related to Marcus Plancius Varus, a citizen of Perga, who was proconsular governor of Bithynia and Pontus. Further, at least one authority believes Cornutus is the father of Julia Tertulla. However, Julia Tertulla married Lucius Julius Marinus Caecilius Simplex, who was suffect consul in 101, which indicates either Julia was married at a very young age, or would be better considered Cornutus' sister. Further, Olli Salomies reports an unpublished inscription that proves Cornutus' wife was Plancia Magna (which would explain how that element entered their son's name), and the full name of their son.
His career can be reconstructed from an inscription. There is no information about which board her served as a member of the vigintiviri, so it may be possible Cornutus missed that office in his cursus honorum. Cornutus then was an urban quaestor and aedile Cerialis as he proceeded through the traditional republican magistracies, before being adlected as a praetor by Vespasian and Titus, likely during their censorship of AD 73/74. With praetorian rank, Cornutus held two more offices, first as legate to the proconsular governor of Crete and Cyrenaica, than as proconsular governor of Gallia Narbonensis.