Petronius Arbiter was a Roman courtier during the reign of Nero. The historian Tacitus identifies him as Gaius Petronius, the elegantiae arbiter, or "judge of elegance," at Nero's court. He is described as a refined hedonist who had previously served as consul and governor. He was accused of involvement in the Pisonian conspiracy and, while under arrest, chose a deliberate suicide, sending the emperor a catalog of Nero's debaucheries before dying. The identification of this courtier with the author of the Satyricon is traditional but not absolutely certain.

His sole known work is the Satyricon, a lengthy, episodic comic novel written in prose interspersed with verse. Only fragments survive, the most famous being the "Cena Trimalchionis," or "Banquet of Trimalchio."

Petronius is significant as the author of the Satyricon, the earliest surviving example of the Roman novel. The work is a pioneering comic-realistic fiction that provides a vivid, satirical portrait of social mobility and excess in the early Imperial period. Its mixture of prose and verse, a form known as Menippean satire, and its use of colloquial speech make it a unique literary document.