There were several civil wars in ancient Rome, especially during the late Republic. The most famous of these are the war in the 40s BC between Julius Caesar and the optimate faction of the senatorial elite initially led by Pompey and the subsequent war between Caesar's successors and die hard loyalists, Octavian and Mark Antony in the 30s BC. Following is a list of civil wars in ancient Rome.
- The Crisis of the Roman Republic - an extended period of political historical unrest, from about 133 BC to 30 BC.
- Social War (91–88 BC), between Rome and many of its Italian allies - Roman victory.
- Sulla's first civil war (88–87 BC), between Lucius Cornelius Sulla's supporters and Gaius Marius' forces - Sullan victory.
- Sertorian War (83–72 BC ), between Rome and the provinces of Hispania under the leadership of Quintus Sertorius, a supporter of Gaius Marius - Sullan victory.
- Sulla's second civil war (82–81 BC), between Sulla and Marius' supporters - Sullan victory.
- Lepidus' rebellion (77 BC), when Lepidus rebelled against the Sullan regime.
- Catiline Conspiracy (63–62 BC), between the Senate and the dissatisfied followers of Catiline - Senatorial victory.
- Caesar's Civil War (49–45 BC), between Julius Caesar and the Optimates initially led by Pompey the Great (Gnaeus Pompeius Magnus) - Caesarean victory.
- Post-Caesarian civil war (44–43 BC), between the Senate's army (led first by Cicero and then by Octavianus) and the army of Antonius, Lepidus, and their colleagues - Truce results in union of forces.
- Liberators' civil war (44–42 BC), between the Second Triumvirate and the Liberators (Brutus and Cassius, Caesar's assassins) - Triumvirate victory.
- Sicilian revolt (44–36 BC), between the Second Triumvirate (particularly Octavianus and Agrippa) and Sextus Pompey, the son of Pompey - Triumvirate victory.
- Perusine War (41–40 BC), between the forces of Octavianus against Lucius Antonius and Fulvia (the younger brother and wife of Marcus Antonius) - Octavius victory.
- Final War of the Roman Republic (32–31 BC), between Octavianus and his friend and general Agrippa against Marcus Antonius and Cleopatra VII Philopator - Octavius victory.
- Year of the Five Emperors and subsequent civil war (193–197), between the generals Septimius Severus, Pescennius Niger and Clodius Albinus following the assassination of Commodus (AD 192) and the subsequent murders of Pertinax and Didius Julianus (AD 193). Severus is victorious and founds the Severan dynasty.
- Civil War of 218, fought between the Emperor Macrinus and his rival Elagabalus and resulting in Macrinus' downfall and his replacement by Elagabalus.
- Year of the Six Emperors (238), between various generals against Maximinus Thrax and after his murder. After Gordian I and Gordian II are defeated by a pro-Maximinus Army following an attempt to overthrow the emperor, Maximinus is assassinated. Pupienus, Balbinus, and Gordian III replace him, but the former two are assassinated within months and only Gordian III survives.
- Throughout the Crisis of the Third Century (AD 235–284), various generals fought with each other to become emperor and emperors fought against usurpers, resulting in non-stop civil war.
- Civil wars of the Tetrarchy (306–324), beginning with the usurpation of Maxentius and the defeat of Flavius Valerius Severus, and ending with the defeat of Licinius at the hands of Constantine I in 324 AD. The Tetrarchy established by Diocletian would break up because of these wars.
- Civil War of 350–353, when the emperor Constantius II defeated the usurper Magnentius.
- Civil War of 387–388, when the Eastern Emperor Theodosius I defeated the Western Emperor Magnus Maximus.
- Civil War of 392–394, when the Eastern Emperor Theodosius I defeated the usurper Eugenius.
- Gildonic revolt (AD 398), when the Comes Gildo rebelled against the Western Emperor Honorius. The revolt was subdued by Flavius Stilicho, the magister militum of the Western Roman empire.
- Civil War of 432, when the Magister militum Flavius Aetius was defeated by the rival Magister militum Bonifacius, who died of wounds sustained in battle soon afterwards, giving Aetius full control over the Western Empire.
- Kohn, George Childs, 'Dictionary of Wars, Revised Edition' (Checkmark Books, New York, 1999)