A lex Julia refers to any ancient Roman law introduced by a member of the gens Julia, a prominent patrician family. While the term can apply to various legislative acts throughout Roman history, it is most frequently associated with specific reforms enacted during the late Republic and early Empire.
In common historical usage, the term often refers to the moral legislation introduced by Augustus in 23 BC. Alternatively, it may refer to significant legal measures associated with Julius Caesar, reflecting the family's enduring influence on the Roman legal and political landscape.