The Social War (also called the Italian War) was a war from 91 – 88 BC between the Romans and the other cities in Italy.

In 90 BC almost all of the Italian allies of Rome rebelled in what the Romans called the Social War, allies in Latin being Socii, related to the English "associates". The allied cities in the Italian peninsula had sought for some time Roman citizenship and therefore more of a say in the external policy of the Roman Republic — most local affairs came under local governance and were not as important to the Romans as, for example, when the alliance would go to war or how they would divide the plunder. Rome undercut the military rebellion by extending citizenship to all of Italia south of the Po River and then spent two years defeating the cities still in arms. Lucius Cornelius Sulla came to prominence as an officer in this war. Roman citizenship and the right to vote was limited, as always in the ancient world, by the requirement of physical presence on voting day. After 88 BC candidates regularly paid the expenses at least partially for their supporters to travel to Rome in order to vote.