Quintus Metellus Celer was a Roman tribune in the 1st century BC, and a correspondent of Marcus Tullius Cicero. He became an ally and brother-in-law of Pompey the Great through Pompey's marriage to Celer's half-sister Mucia Tertia, and served as legate in Asia during Pompey's campaigns in the east. When Pompey divorced Murcia in 61, possibly for adultery, Celer took umbrage and joined Pompey's political opponents. In 60 BC as consul Celer opposed Pompey's political settlements in the east, and his allotment of land to veterans of his eastern campaigns.
Celer's reputation was dogged by the scandals attached to his wife, Clodia, the wayward sister of the notorious Publius Clodius Pulcher. A contemporary poem by Catullus "may refer to Celer's marital ineffectiveness and obtuseness". The marriage produced a daughter, Caecilia. The couple were known for their blazing public rows. When Celer died in 59 BC, of unknown causes, gossip made Clodia his suspected poisoner.
In 62 BC Celer's brother, Quintus Metellus Nepos, challenged the legality of Cicero's actions in dealing with the Catiline conspiracy. Celer, who was serving proconsular governor of Gaul, wrote in support of Cicero. The charge was dismissed.