Violence erupts after the Apprentice Boys of Derry march in Derry, Northern Ireland, resulting in a three-day communal riot known as the Battle of the Bogside.

The Battle of the Bogside was a large three-day riot that took place from 12 to 14 August 1969 in Derry, Northern Ireland. Thousands of Catholic/Irish nationalist residents of the Bogside district, organised under the Derry Citizens' Defence Association, clashed with the Royal Ulster Constabulary (RUC) and loyalists. It sparked widespread violence elsewhere in Northern Ireland, led to the deployment of British troops, and is often seen as the beginning of the thirty-year conflict known as the Troubles.

Violence broke out as the Protestant loyalist Apprentice Boys marched past the Catholic Bogside. The RUC drove back the Catholic crowd and pushed into the Bogside, followed by loyalists who attacked Catholic homes. Thousands of Bogside residents beat back the RUC with a hail of stones and petrol bombs. The besieged residents built barricades, set up first aid posts and petrol bomb workshops, and a radio transmitter broadcast messages calling for resistance. The RUC fired CS gas into the Bogside the first time it had been used by UK police. Residents feared the Ulster Special Constabulary would be sent in and would massacre Catholic residents.The Irish Army set up field hospitals near the border and the Irish government called for a United Nations peacekeeping force to be sent to Derry. On 14 August, the British Army were deployed and the RUC were withdrawn. The British Army made no attempt to enter the Bogside, which became a no-go area called Free Derry. This situation continued until October 1969 when military police were allowed in.

The Apprentice Boys of Derry is a Protestant fraternal society with a worldwide membership of over 10,000, founded in 1814 and based in the city of Derry, Northern Ireland. There are branches in Ulster and elsewhere in Ireland, Scotland, England, Australia and Toronto, Canada. The society aims to commemorate the 1689 Siege of Derry when Catholic James II of England and Ireland and VII of Scotland laid siege to the walled city, which was at the time a Protestant stronghold. Apprentice Boys parades once regularly led to virulent opposition from the city's Irish nationalist majority, but recently a more conciliatory approach has taken place and now the parades are virtually trouble-free. The 2014 'Shutting of the Gates' parade was described as "the biggest in years" and was violence-free.