Lucius Domitius Ahenobarbus, consul 54 BC, was an enemy of Julius Caesar and a strong supporter of the party in the late Roman Republic.
He is first mentioned in 70 BC by Cicero as a witness against Verres. In 61 BC he was curule aedile, when he exhibited a hundred Numidian lions, and continued the games so long that the people were obliged to leave the circus before the exhibition was over, in order to take food, which was the first time they had done so. This pause in the games was called diludium.
He married Porcia, the sister of Cato the Younger, and in his aedileship supported the latter in his proposals against bribery at elections, which were directed against Pompey, who was purchasing votes for Afranius. The political opinions of Ahenobarbus coincided with those of Cato; he was throughout his life one of the strongest supporters of the aristocratic party. He took an active part opposing the measures of Julius Caesar and Pompey, and in 59 BC was accused, at the instigation of Caesar, of being an accomplice to the pretended conspiracy against Pompey's life.
Ahenobarbus was praetor in 58 BC. He was candidate for the consulship of 55 BC, and threatened that he would in his consulship carry into execution the measures he had proposed in his praetorship, and deprive Caesar of his province. He was defeated, however, by Pompey and Crassus, who became candidates, and was driven from the Campus Martius on the day of election by force of arms. He became a candidate again in the following year, and Caesar and Pompey, whose power was firmly established, did not oppose him. He was accordingly elected consul for 54 BC with Appius Claudius Pulcher, a relation of Pompey's, but was not able to effect anything against Caesar and Pompey. Both men were involved in an election scandal that year. He did not go to a province at the expiration of his consulship; and as the friendship between Caesar and Pompey cooled, he became closely allied with the latter.