Gnaeus Domitius Ahenobarbus (11 December 17 BC – January 41 AD) was a close relative of the five Roman Emperors of the Julio-Claudian dynasty.
Domitius was the only son of Antonia Major (niece of the emperor Augustus and daughter of Augustus' sister Octavia Minor who was married to triumvir Mark Antony) and Lucius Domitius Ahenobarbus (consul 16 BC).
His only siblings were Domitia Lepida the Elder and Domitia Lepida the Younger, mother of the Empress Valeria Messalina (third wife of the Emperor Claudius).
He was a great-nephew of the Emperor Augustus, brother-in-law and first cousin once removed of the Emperor Caligula; maternal cousin of the Emperor Claudius and the biological father to the Emperor Nero.