The following outline is provided as an overview of and topical guide to the Troubles.

The Troubles – historical 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.

Laws in both the Republic of Ireland and the UK proscribe (ban) membership of a number of Irish republican and Ulster loyalist groups. Several other smaller paramilitary factions have appeared throughout the Troubles, and some groups have used cover-names to deflect responsibility for attacks.

In this context, operational refers to the period during which the 'official' paramilitary campaign was conducted.

Umbrella groups

• Irish Republican Socialist Movement
• Provisional Republican Movement

Umbrella groups

• Ulster Army Council (UAC)
• Ulster Loyalist Central Co-ordinating Committee (ULCCC)
• Combined Loyalist Military Command (CLMC)

• Protestant Action Force – Used by the UVF to claim sectarian attacks.
• South Armagh Republican Action Force – Used by the PIRA's South Armagh Brigade to claim sectarian attacks in the mid-1970s
• Catholic Reaction Force – Used by the INLA to claim sectarian attacks.
• Armagh People's Republican Army & People's Liberation Army – was used by the INLA to claim some of their earliest attacks, mostly in 1975.
• Ulster Freedom Fighters – Used by the UDA to claim violent attacks.
• Red Hand Brigade – Was used as a cover by the Glenanne gang members who carried out the Dublin and Monaghan bombings in May 1974.^[1]

In the table below:

• The period of activity for republican groups is shown in green.
• The period of activity for loyalist groups is shown in orange.
• The period of ceasefire is shown in grey.

• British Army
  • Territorial Army
  • Force Research Unit
  • Military Reaction Force
• Royal Air Force
• Royal Navy
• Metropolitan Police
• MI5
• GCHQ
• Secret Intelligence Service

• Royal Ulster Constabulary (RUC)
  • RUC Special Branch
• Ulster Special Constabulary (USC) – to 30 April 1970
• Northern Ireland Prison Service (NIPS)
• Ulster Defence Regiment (UDR) – from 1 January 1970 to 30 June 1992
• Royal Irish Regiment (RIR) – from 1 July 1992

• Irish Army
• Garda Síochána (police)

Listing includes brief summary of ideology and position on the Good Friday Agreement 1998.

• Sinn Féin (SF). President: Mary Lou MacDonald. Militant nationalist. Associated with the Provisional IRA. Translation from Irish: "We Ourselves".
• The Social Democratic and Labour Party (SDLP). Leader: Colum Eastwood. Moderate centre-left nationalist.
• The Workers' Party (WP). Leadership Disputed between Michael McCorry and Ted Tynan.^[2] Marxist nationalist. Formerly Official Sinn Féin.

• The Irish Republican Socialist Party (IRSP). Militant socialist nationalist. Political wing of INLA. Have been on ceasefire since 1998.
• Republican Sinn Féin (RSF). President: Seosamh Ó Maoileoin. Militant nationalist. Associated with the Continuity IRA.
• The 32 County Sovereignty Movement (32CSM). President: Francis Mackey. Militant nationalist. Associated with the Real IRA.
• The Republican Network for Unity (RNU). Militant nationalist. Accused by Police Service of Northern Ireland (PSNI) of being the political wing of Óglaigh na hÉireann (Real IRA splinter group), however this is rejected by both groups.

• Fianna Fáil
• Fine Gael
• Green Party
• Renua

• The Democratic Unionist Party (DUP). Leader: Jeffrey Donaldson. Radical populist unionist. Originally anti-Agreement.
• The Ulster Unionist Party (UUP). Leader: Doug Beattie. Moderate conservative unionist.
• The Progressive Unionist Party (PUP). Leader: Russell Watton. Moderate centre-left unionist. Political wing of Ulster Volunteer Force.
• The Conservative Party also organises and contests elections in Northern Ireland. Moderate unionist.

• Traditional Unionist Voice (TUV). Leader: Jim Allister. Old school loyalist.

• The Alliance Party of Northern Ireland. Leader: Naomi Long. Liberal cross-community. Pro-Agreement
• The Green Party. Environmentalist. Pro-Agreement.
• Ulster Third Way. Supports Northern Ireland independence.

1921–1972

• Governor
• Prime Minister
• Cabinet

1998–

• First Minister and deputy First Minister
• Executive

1921–1972
The Parliament of Northern Ireland:

• House of Commons
• Senate

1972–1998

• The Northern Ireland Assembly (1973–1974)
• The Northern Ireland Constitutional Convention (1975–1976)
• The Northern Ireland Assembly (1982–1986)
• The Northern Ireland Forum (1996–1998)

1998–

• The Northern Ireland Assembly

• Taoiseach (prime minister)
• Department of Defence
• Department of Foreign Affairs
• Dáil Éireann (assembly)
• Seanad Éireann (senate)

• Prime Minister
• The Ministry of Defence (MOD)
• The Northern Ireland Office (NIO)
• The House of Commons
• The House of Lords
• The Northern Ireland Affairs Committee (House of Commons)
• The Northern Ireland Grand Committee (House of Commons)

• British–Irish Council (BIC)
• British–Irish Inter-Parliamentary Body
• North/South Ministerial Council (NSMC)

• Sunningdale Agreement (1973)
• Anglo-Irish Agreement (1985)
• Downing Street Declaration (1993) and principle of consent
• Establishment of the IICD (1997)
• Belfast Agreement (1998)
• Amendment of Articles 2 and 3 (1999)
• Establishment of the Independent Monitoring Commission (2003)
• IRA ceasefire and decommissioning (2005)
• St Andrews Agreement (2006)

• Roman Catholic Church in Ireland
• Church of Ireland (Anglican)
• Presbyterian Church in Ireland
• Methodist Church in Ireland
• Free Presbyterian Church of Ulster

• The Gaelic Athletic Association (GAA)

• The Apprentice Boys of Derry
• The Orange Institution
• The Independent Orange Order
• The Royal Black Institution

• The Ancient Order of Hibernians (AOH)