Sextus Julius Caesar Sex. f. L. n. was a Roman statesman, and the first member of the Julii Caesares to hold the consulship, which he attained in 157 BC.
From his filiation, we know that Sextus' father was also named Sextus, and that his grandfather was named Lucius. In his reconstruction of the family, classical scholar Wilhelm Drumann assumed that he was the son of Sextus Julius Caesar, one of the military tribunes if 181 BC, and the grandson of an otherwise unknown Lucius Julius Caesar, who would have been the son of Sextus, praetor in 208 BC. However, more recent scholarship has concluded that the military tribune and the consul were the same person, and that his father was the praetor of 208.
Sextus had at least one brother, Lucius, who was praetor in 183 BC, and probably a second, Gaius, who was a senator and the great-grandfather of Gaius Julius Caesar, the dictator. He had two sons: Sextus, who was praetor urbanus in 123 BC, and Lucius, by whom he was the grandfather of Lucius Julius Caesar, consul in BC 90, and the orator Gaius Julius Caesar Strabo Vopiscus.
In 181 BC, Sextus served as a military tribune under Lucius Aemilius Paullus Macedonicus, proconsul of Liguria. In 170, he was one of the legates sent to Thrace in order to restore liberty to the people of Abdera, and to seek out and return those who had been sold into slavery. In 165, Sextus was one of the curule aediles. At the Megalesian Games, he and his colleague, Gnaeus Cornelius Dolabella, gave the first, unsuccessful presentation of Terence's comedy, Hecyra. Sextus subsequently held the praetorship; the exact year is uncertain, but it was no later than 160.