During 12–16 August 1969, there was an outbreak of political and sectarian violence throughout Northern Ireland, which is often seen as the beginning of the thirty-year conflict known as the Troubles. There had been sporadic violence throughout the year arising out of the Northern Ireland civil rights campaign, which demanded an end to discrimination against Catholics and Irish nationalists. Civil rights marches had been attacked by Protestant loyalists, and protesters often clashed with the Royal Ulster Constabulary (RUC), the overwhelmingly Protestant police force.

On 12 August, the Battle of the Bogside erupted in Derry: three days of fierce clashes between the RUC and thousands of Catholic/nationalist residents of Derry's Bogside district. The besieged residents built barricades and set up first aid posts and workshops for making petrol bombs. Police fired CS gas at rioters for the first time in the history of the UK. In support of the Bogsiders, on 13 August Catholics/nationalists held protests elsewhere in Northern Ireland, some of which led to violence. The bloodiest clashes were in Belfast, where seven people were killed and hundreds wounded, five of them Catholic civilians shot by police. Protesters clashed with both the police and with loyalists, who attacked Catholic districts. Scores of homes and businesses were burnt out, most of them owned by Catholics, and thousands of mostly Catholic families were driven from their homes. In some cases, police helped the loyalists and failed to protect Catholic areas. Both republican and loyalist paramilitaries were involved in the clashes. There were also clashes between protesters and police in Armagh, where a protester was killed by police, as well as in Dungannon and Newry.

The British Army was deployed to restore order on 14 August, beginning the thirty-seven year Operation Banner, and peace lines were built to separate Catholic and Protestant districts. The Republic of Ireland's government set up field hospitals and refugee centres near the Irish border, and called for a United Nations peacekeeping force to be sent to Northern Ireland. The British government held an inquiry into the riots, and the reserve police force was disbanded. The riots led to a split within the IRA and the formation of the Provisional Irish Republican Army and the Official Irish Republican Army. It also led to the growth of loyalist paramilitaries such as the Ulster Volunteer Force (UVF).

Northern Ireland was destabilised in 1968 by sporadic rioting arising out of the Northern Ireland Civil Rights Association (NICRA) campaign, and the police and loyalist reaction to it. The civil rights campaign demanded an end to discrimination against Catholics in voting rights, housing and employment. NICRA was opposed by loyalists led primarily by Ian Paisley.^{[citation needed]}

During the summer of 1969, the International Commission of Jurists (ICJ) published a highly critical report which "criticised the Northern Ireland Government for police brutality, religious discrimination [against Catholics] and gerrymandering in politics". The ICJ secretary general said that laws and conditions in Northern Ireland had been cited by the South African government to justify its apartheid system. The Times reported that the Ulster Special Constabulary (B-Specials), Northern Ireland's reserve police force, was "regarded as the militant arm of the Protestant Orange Order". The Belfast Telegraph reported that the ICJ had added Northern Ireland to the list of states/jurisdictions "where the protection of human rights is inadequately assured".

The first major confrontation between Catholic civil rights activists and the Royal Ulster Constabulary (RUC), Northern Ireland's overwhelmingly Protestant police force, occurred in Derry on 5 October 1968, when a NICRA march was baton-charged by the RUC. Disturbed by the prospect of major violence, the prime minister of Northern Ireland, Terence O'Neill, promised reforms in return for a "truce", whereby no further demonstrations would be held.^{[citation needed]}

In spite of these promises, in January 1969 People's Democracy, a left-wing group, staged an anti-government march from Belfast to Derry. Loyalists, including off-duty members of the B-Specials, attacked the marchers, most determinedly at Burntollet Bridge, outside Derry. The RUC failed to adequately protect the marchers. This action, and the RUC's subsequent entry into Derry's predominantly Catholic Bogside district, led to serious rioting in the city.

In March and April 1969, there were six bomb attacks on electricity and water infrastructure, causing blackouts and water shortages. At first the attacks were blamed on the Irish Republican Army (IRA), but it later emerged that the loyalist Ulster Protestant Volunteers (UPV) and Ulster Volunteer Force (UVF) had carried out the bombings in an attempt to implicate the IRA, destabilise the Northern Ireland government and halt the reforms promised by O'Neill.