In many legal jurisdictions related to English common law, affray is a public order offence consisting of the fighting of one or more persons in a public place to the terror of ordinary people. Depending on their actions, and the laws of the prevailing jurisdiction, those engaged in an affray may also render themselves liable to prosecution for assault, unlawful assembly, or riot; if so, it is for one of these offences that they are usually charged.

The Riot Act, sometimes called the Riot Act 1714 or the Riot Act 1715, was an act of the Parliament of Great Britain which authorised local authorities to declare any group of 12 or more people to be unlawfully assembled and order them to disperse or face punitive action. The act's full title was "An Act for preventing tumults and riotous assemblies, and for the more speedy and effectual punishing the rioters", and it came into force on 1 August 1715. It was repealed in England and Wales by section 10(2) and Part III of Schedule 3 of the Criminal Law Act 1967. Acts similar to the Riot Act passed into the laws of British colonies in Australia and North America, some of which remain in force today.