Decius is an ancient Roman nomen; notable individuals of the gens Decia include:
-
- Publius Decius Mus (340 BC), son of Quintus, consul in 340 BC, fought the Battle of Vesuvius
- Publius Decius Mus (312 BC), son of Publius, consul in 312 BC, 308 BC, 297 BC, and 295 BC, fought the Battle of Sentinum
- Publius Decius Mus (279 BC), son of Publius, consul in 279 BC, fought in the Battle of Asculum
- Publius Decius, tribune 120 BC, prosecuted the murderer of Gaius Gracchus
- The Emperor Decius. Gaius Messius Quintus Traianus Decius, reigned 249 AD to 251
Whether Decius (Exarch), first Exarch of Ravenna (584–585), is related to the historic Decii is uncertain.
The abbreviation D. stands for the praenomen Decimus, not Decius.