For the Roman emperor Gaius, see Caligula.
Gaius or Caius was a common Roman praenomen. It is abbreviated C.; the abbreviation goes back to before the Roman alphabet distinguished between C and G. Some individuals with this name are:
- Gaius (jurist), the jurist (the rest of his name is unknown)
- Gaius Acilius
- Gaius Antonius
- Gaius Antonius Hybrida
- Gaius Asinius Gallus
- Gaius Asinius Pollio
- Gaius Ateius Capito
- Gaius Aurelius Cotta
- Gaius Baltar from the 2003 revival of Battlestar Galactica
- Gaius Calpurnius Piso
- Gaius Canuleius, a tribune
- Gaius Cassius Longinus
- Gaius Claudius Marcellus
- Gaius Cornelius Tacitus, Roman orator famous for the annals and histories.
- Gaius Duilius
- Gaius Flaminius
- Gaius Flavius Fimbria
- Gaius Gracchus
- Gaius Julius Alpinus Classicianus
- Gaius Julius Antiochus Epiphanes Philopappos, consul and Syrian prince
- Gaius Julius Caesar, most commonly known as simply "Julius Caesar"
- Gaius Julius Caesar Germanicus, most commonly known by his nickname "Caligula"
- Gaius Julius Caesar Strabo Vopiscus
- Gaius Julius Caesar Vipsanianus (or Gaius Vipsanius Agrippa)
- Gaius Julius Callistus
- Gaius Julius Civilis
- Gaius Julius Eurycles
- Gaius Julius Hyginus
- Gaius Julius Marcus
- Gaius Julius Priscus
- Gaius Julius Solinus
- Gaius Julius Vindex, governor of Lusitania
- Gaius Laelius
- Gaius Licinius Stolo
- Gaius Livius Drusus
- Gaius Lucilius
- Gaius Lutatius Catulus
- Gaius Maecenas
- Gaius Marcius Rutilus
- Gaius Marius
- Gaius Matius
- Gaius Memmius
- Gaius Nautius Rutilus
- Gaius Octavius
- Gaius Oppius
- Gaius Papirius Carbo, a consul of 120 BC
- Gaius Papirius Carbo, a tribune of 90 BC
- Gaius Popillius Laenas
- Gaius Rabirius
- Gaius Rubellius Blandus
- Gaius Sallustius Crispus Passienus
- Gaius Servilius Ahala
- Gaius Servilius Glaucia
- Gaius Suetonius Paulinus
- Gaius Valerius Flaccus
- Gaius Valerius Pudens
- Gaius Vipsanius Agrippa (or Gaius Julius Caesar Vipsanianus)
- Gaius Volusenus
- John Caius
- Pope Caius
- Caius, presbyter of Rome
- the third colossus in the game shadow of the colossus
The fictional character Gaius Octavian in the HBO/BBC TV show Rome is loosely based on the historical figure Octavian. Additionally, Gaius Helen Mohiam is a fictional character in the Dune universe; and Gaius Baltar is a fictional character in the television series Battlestar Galactica. In classical times, the name was pronounced in three syllables, Gāius [ˈgɑːius]. Caius (pronounced "Keys") is the common short name for Gonville and Caius College, Cambridge.
