Civil disorder, also known as civil disturbance, civil unrest, civil strife, or turmoil, are situations when law enforcement and security forces struggle to maintain public order or tranquility.

Any number of things may cause civil disorder, whether it is a single cause or a combination of causes; however, most are born from political grievances, economic disparities, social discord, but historically have been the result of long-standing oppression by a group of people towards another.

Civil disorder arising from political grievances can include a range of events, from a simple protest to a mass civil disobedience. These events can be spontaneous, but can also be planned. These events can turn violent when agitators and law enforcers overreact.

Civil disorder has in history arisen from economic disputes, political reasons (such as in opposition to oppressive or tyrannical government forces), religious opposition, racial oppression and social discord among various cases throughout history.

Exploiting a crowd's mood, radicals can manipulate and weaponize a crowd, using skillful agitation to coax the crowd's capacity for violence and turn it into a vengeful mob, directing the crowd's aggression and resentment at the agitator's chosen target.

Tactical agitators can leverage media, including social media, to connect with potential crowd members and incite them to break the law or provoke others, all without direct personal contact. Conversely, a skilled leader can calm or divert a crowd using strategic suggestions, commands, or appeals to reason, aiming to de-escalate a situation.

Emotional contagion plays a significant role in crowd behaviour by fostering a sense of unity among its members. This unity can lead the crowd to adopt a mob mentality and engage in mob behaviour. Crowd members amplify each other's emotions, creating a heightened state of collective emotion. Ideas rapidly spread among the group and to bystanders and mass media.

When emotional contagion prevails, raw emotion is high while self-discipline is low. Personal prejudices and unsatisfied desires – usually restrained – are unabashedly released. This incentivizes crowd membership, as the crowd provides cover for individuals to do things they want to do, but would not dare try to do alone. This incentive can become greater for the crowd than its concern for law and authority, leading to unlawful and disruptive acts. Once the crowd engages in such acts, it effectively becomes a mob – a highly emotional, unreasonable, potentially violent crowd.