Lucius Julius Caesar (fl. 1st century BC) was a Roman politician and senator who was elected consul of the Roman Republic in 64 BC. A supporter of his cousin, the Roman dictator Gaius Julius Caesar, Lucius was a key member of the senatorial faction which strove to avoid civil war between the Roman Senate and Marcus Antonius (Mark Antony) in the aftermath of the Dictator's assassination.
A member of the patrician gens Julia, Lucius Julius Caesar was the son of the consul of 90 BC, also named Lucius Julius Caesar. He began his political career serving as Quaestor in the Roman Province of Asia in 77 BC, probably under Terentius Varro. By 69 BC Lucius had been elected to the priestly position of Augur, and by the end of 67 BC, he had served in the office of Praetor It has been speculated that Lucius was appointed Roman governor of Macedonia between 71 and 68 BC.
Lucius Caesar was then elected Roman consul for 64 BC, serving alongside Gaius Marcius Figulus. During his consulship, senatorial decrees were passed which limited the number of attendants who could accompany candidates during election campaigns, as well as making guilds and societies illegal. During the following year (63 BC), he, together with his cousin, the future Roman dictator Gaius Julius Caesar, were appointed to a two-man committee (Duumviri Perduellionis), for the purpose of bringing the senator Gaius Rabirius to trial for Perduellio.