Bloody Sunday, or the Bogside Massacre, was a massacre on 30 January 1972 when British soldiers shot 26 unarmed civilians during a protest march in the Bogside area of Derry, Northern Ireland. Thirteen men were killed outright and the death of another man four months later was attributed to gunshot injuries from the incident. Many of the victims were shot while fleeing from the soldiers, and some were shot while trying to help the wounded. Other protesters were injured by shrapnel, rubber bullets, or batons, two were run down by British Army vehicles, and some were beaten. All of those shot were Catholics. The march had been organised by the Northern Ireland Civil Rights Association (NICRA) to protest against internment without trial. The soldiers were from the 1st Battalion of the Parachute Regiment, the same battalion implicated in the Ballymurphy massacre several months before.

The Provisional Irish Republican Army, officially known as the Irish Republican Army and informally known as the Provos, was an Irish republican paramilitary force that sought to end British rule in Northern Ireland, facilitate Irish reunification and bring about an independent republic encompassing all of Ireland. It was the most active republican paramilitary group during the Troubles. It argued that the all-island Irish Republic continued to exist, and it saw itself as that state's army, the sole legitimate successor to the original IRA from the Irish War of Independence. It was designated a terrorist organisation in the United Kingdom and an unlawful organisation in the Republic of Ireland, both of whose authority it rejected.