The Dublin and Monaghan bombings of 17 May 1974 were a series of co-ordinated bombings in counties Dublin and Monaghan, Ireland. Three bombs exploded in Dublin during the evening rush hour and a fourth exploded in Monaghan almost ninety minutes later. They killed 33 civilians and injured almost 300. The bombings were the deadliest attack of the conflict known as the Troubles, and the deadliest attack in the Republic's history. Most of the victims were young women, although the ages of the dead ranged from 19 up to 80 years.

The Ulster Volunteer Force (UVF), a loyalist paramilitary group from Northern Ireland, claimed responsibility for the bombings in 1993. It had launched a number of attacks in the Republic since 1969. There are allegations taken seriously by inquiries that elements of the British state security forces helped the UVF carry out the bombings, including members of the Glenanne gang. Some of these allegations have come from former members of the security forces. The Irish parliament's Joint Committee on Justice called the attacks an act of international terrorism involving British state forces. The month before the bombings, the British government had lifted the UVF's status as a proscribed organisation.

The bombings happened during the Ulster Workers' Council strike. This was a general strike called by hardline loyalists and unionists in Northern Ireland who opposed the Sunningdale Agreement. Specifically, they opposed the sharing of political power with Irish nationalists, and the proposed role for the Republic in the governance of Northern Ireland. The Republic's government had helped bring about the Agreement. The strike brought down the Agreement and the Northern Ireland Assembly on 28 May.

No one has ever been charged with the bombings. A campaign by the victims' families led to an Irish government inquiry under Justice Henry Barron. His 2003 report criticised the Garda Sochna's investigation and said the investigators stopped their work prematurely. It also criticised the Fine Gael/Labour government of the time for its inaction and lack of interest in the bombings. The report said it was likely that British security force personnel or MI5 intelligence was involved but had insufficient evidence of higher-level involvement. However, the inquiry was hindered by the British government's refusal to release key documents. The victims' families and others are continuing to campaign to this day for the British government to release these documents.

The Troubles (Irish: Na Trioblóidí) were an ethno-nationalist conflict in Northern Ireland that lasted about 30 years from the late 1960s to 1998. Also known internationally as the Northern Ireland conflict, it is sometimes described as an "irregular war" or "low-level war". The conflict began in the late 1960s and is usually deemed to have ended with the Good Friday Agreement of 1998. Although the Troubles mostly took place in Northern Ireland, at times violence spilled over into parts of the Republic of Ireland, England and mainland Europe.

The conflict was primarily political and nationalistic, fuelled by historical events. It also had an ethnic or sectarian dimension but despite use of the terms 'Protestant' and 'Catholic' to refer to the two sides, it was not a religious conflict. A key issue was the status of Northern Ireland. Unionists and loyalists, who for historical reasons were mostly Ulster Protestants, wanted Northern Ireland to remain within the United Kingdom. Irish nationalists and republicans, who were mostly Irish Catholics, wanted Northern Ireland to leave the United Kingdom and join a united Ireland.

The conflict began during a campaign by the Northern Ireland Civil Rights Association to end discrimination against the Catholic/nationalist minority by the Protestant/unionist government and local authorities. The government attempted to suppress the protests. The police, the Royal Ulster Constabulary (RUC), were overwhelmingly Protestant and accused of sectarianism and police brutality. The campaign was also violently opposed by loyalists, who said it was a republican front. Increasing tensions led to the August 1969 riots and the deployment of British troops, in what became the British Army's longest operation. "Peace walls" were built in some areas to keep the two communities apart. Some Catholics initially welcomed the British Army as a more neutral force than the RUC, but soon came to see it as hostile and biased, particularly after Bloody Sunday in 1972.The main participants in the Troubles were republican paramilitaries such as the Provisional Irish Republican Army (IRA) and the Irish National Liberation Army (INLA); loyalist paramilitaries such as the Ulster Volunteer Force (UVF) and Ulster Defence Association (UDA); British state security forces such as the British Army and RUC; and political activists. The security forces of the Republic of Ireland played a smaller role. Republicans carried out a guerrilla campaign against British forces as well as a bombing campaign against infrastructural, commercial and political targets. Loyalists attacked republicans/nationalists and the wider Catholic community in what they described as retaliation. At times, there were bouts of sectarian tit-for-tat violence, as well as feuds within and between paramilitary groups. The British security forces undertook policing and counter-insurgency, primarily against republicans. There were incidents of collusion between British state forces and loyalist paramilitaries. The Troubles also involved numerous riots, mass protests and acts of civil disobedience, and led to increased segregation and the creation of temporary no-go areas.

More than 3,500 people were killed in the conflict, of whom 52% were civilians, 32% were members of the British security forces and 16% were members of paramilitary groups. Republican paramilitaries were responsible for some 60% of the deaths, loyalists 30% and security forces 10%. The Northern Ireland peace process led to paramilitary ceasefires and talks between the main political parties, which resulted in the Good Friday Agreement of 1998. This Agreement restored self-government to Northern Ireland on the basis of "power-sharing" and it included acceptance of the principle of consent, commitment to civil and political rights, parity of esteem, police reform, paramilitary disarmament and early release of paramilitary prisoners. There has been sporadic violence since the Agreement, including punishment attacks and a campaign by dissident republicans.