From 6 to 11 July 1997 there were mass protests, fierce riots, and gun battles in Irish nationalist districts of Northern Ireland. Irish nationalists/republicans, in some cases supported by the Provisional Irish Republican Army (IRA), attacked the Royal Ulster Constabulary (RUC) and British Army. The protests and violence were sparked by the decision to allow the Orange Order (a Protestant, unionist organization) to march their traditional route, passing through a Catholic/nationalist neighbourhood of Portadown. Irish nationalists were outraged by the decision and by the RUC's aggressive treatment of those protesting against the march. There had been a bitter dispute over the march for many years.

It was the last spell of widespread violence in Northern Ireland before the signing of the Good Friday Agreement in April 1998. RUC and British Army patrols were attacked hundreds of times by rioters throwing stones and petrol bombs, and by IRA members with automatic rifles and grenades. They fired more than 2,500 plastic bullets at rioters and exchanged gunfire with the IRA. More than 100 civilians and 65 security force personnel were injured. There were many complaints of police brutality and a 13-year-old boy went into a coma after being struck on the head by a plastic bullet. Hundreds of vehicles were hijacked, set on fire and used to block roads in Belfast and other districts like Newry, Armagh and Dungannon. The RUC and the British troops had to withdraw entirely from some nationalist areas of Belfast. The Provisional IRA's involvement in the clashes was its last major action during its 27-year campaign. The paramilitary organization declared its last ceasefire on 19 July.

The Orange Order is a Protestant, unionist fraternal organization. It insists that it should be allowed to march its traditional route to-and-from Drumcree Church each July. It had marched this route since 1807, when the area was mostly farmland. However, today most of this route is through the mainly Catholic/Irish nationalist part of Portadown. The residents sought to re-route the march away from their area, seeing it as "triumphalist" and "supremacist". They likened it to a Ku Klux Klan march through an African American neighbourhood.

The march was first banned in 1832, although the law was ignored by the Orangemen. Local magistrate William Hancock wrote in 1835: "For some time past the peaceable inhabitants of the parish of Drumcree have been insulted and outraged by large bodies of Orangemen parading the highways, playing party tunes, firing shots, and using the most opprobrious epithets they could invent... a body of Orangemen marched through the town and proceeded to Drumcree church, passing by the Catholic chapel though it was a considerable distance out of their way." The onset of the Troubles in 1969 led to the dispute intensifying and triggered a shift in the local population that further strengthened the ethnic divide. In 1987, the Orangemen were banned from marching along Obins Street, after their march caused severe rioting two years in a row. However, the Orangemen were still allowed to march along the other main road in the Catholic area, the Garvaghy Road.

In 1995, residents formed the Garvaghy Road Residents Coalition (GRRC) to try and divert the march away from Garvaghy Road. The dispute escalated that July when residents blocked Garvaghy Road for two days. Orangemen and their supporters clashed with the Royal Ulster Constabulary (RUC) until the residents were persuaded to clear the road and the march went ahead.

The July 1996 march was banned from Garvaghy Road. Thousands of Orangemen and their supporters gathered at Drumcree and there was a three-day standoff with the RUC. They held large protests and attacked the police and Catholics throughout Northern Ireland. The Loyalist Volunteer Force (LVF) shot dead a Catholic taxi driver and threatened further attacks. As a result, the ban was lifted. Police violently removed nationalist protesters from Garvaghy Road and forced the march through. This sparked days of rioting in Catholic/nationalist areas of Northern Ireland; one protester was crushed to death by a British Army armoured vehicle in Derry (see 1996 Derry riots).

On 18 June 1997, Alistair Graham warned after the killing of two RUC officers in nearby Lurgan that the IRA was seeking to raise tensions before the march so that a compromise would be impossible.

In June 1997, Secretary of State Mo Mowlam had privately decided to let the march proceed. However, in the days leading up to the march, she insisted that no decision had been made. She met Taoiseach Bertie Ahern, who stressed that any unilateral decision to allow the march would be 'a mistake'. The RUC and the Northern Ireland Office said they would announce their decision two or three days before the march. According to a document leaked from the Public Records Office of Northern Ireland in 2021, on 9 June the RUC requested heavy equipment to government agencies in order to remove roadblocks and barricades set up by potential rioters. It was also revealed that the British Army was measuring Garvaghy Road for the possible deployment of bollards.