Quintus Marcius Rex was a name used by men of the gens Marcia in Ancient Rome. They belonged to the Marcii Reges, a family who were the relatives of Julius Caesar through his grandmother Marcia.
Quintus Marcius Rex, praetor in 144 BC, famously known for the Aqua Marcia aqueduct which he constructed and was named after him.
Quintus Marcius Q. f. (Q. n.) Rex, consul in 68 BC, grandson of the consul in 118 BC and a second cousin of Julius Caesar, also a brother-in-law of Publius Clodius Pulcher.