Petronius Arbiter (?-ad 66), Roman writer, believed to have written Satyricon. His full name was probably Gaius (or Titus) Petronius Niger. He was referred to as Arbiter Elegantiae (“judge of elegance”) by the Roman historian Tacitus. Because of his sense of luxury and elegance, Petronius planned many of the entertainments at Nero's court. Petronius also served as proconsul of Bithynia, and later consul. His influence on Nero aroused the jealousy of the politician Ofonius Tigellinus, another of Nero's favorites, who brought false accusations against him; these aroused Nero's anger, and Petronius, realizing that his death was inevitable, committed suicide at Cumae. Before his death he is said to have written and dispatched to Nero a paper containing an account of the tyrant's vices.

Petronius is generally believed to have been the author of a remarkable work of fiction, a satirical romance in prose and verse titled Satyricon (circa 60), parts of which have survived. The Satyricon is memorable as the earliest example in European literature of the picaresque novel and is the prototype of such novels as Gil Blas of Santillane (1715-35; trans. 1749) by Alain Lesage and Roderick Random (1748) by Tobias Smollett.

Satyricon is a unique, often extremely bawdy, description of life in the 1st century ad. Although the narrator speaks in the best Latin of the Silver Age, the work is especially valuable for the colloquialisms and solecisms in the speeches of many of the characters. The most famous episode of the fragmentary work is Trimalchio's banquet, a realistic description of a banquet given by an ostentatious newly rich freedman. Satyricon was the basis of a film (1969) by the Italian director Federico Fellini.