Quintus Marcius Rex (consul 68 BCE)

Quintus Marcius Rex was a consul of the Roman Republic.

He was the grandson of another Quintus Marcius Rex, the consul of 118 BC. He was elected consul for 68 BC with Lucius Caecilius Metellus. Caecilius Metellus died near the start of the year and was not replaced. Marcius went to serve in Cilicia as proconsul and, pressured by his brother-in-law, Publius Clodius, refused to help Lucius Licinius Lucullus. He gave up his province in 66 BC to comply with the "lex Manilia" that gave command of the provinces of the east to Gnaeus Pompeius Magnus.

He was denied a triumph upon his return. He was still waiting outside the city for a triumph when the Catilinarian Conspiracy broke out in 63 BCE. He was sent to watch the movements of Gaius Manlius, Catilina's general. He refused to listen to Manlius's offers of peace.

Marcius had married the eldest sister of Publius Clodius. He died in 61 without leaving an inheritance to his brother-in-law as he expected.