The Glenanne gang or Glenanne group was a secret informal alliance of Ulster loyalists who carried out shooting and bombing attacks against Catholics and Irish nationalists in the 1970s, during the Troubles. Most of its attacks took place in the "murder triangle" area of counties Armagh and Tyrone in Northern Ireland. It also launched some attacks elsewhere in Northern Ireland and in the Republic of Ireland. The gang consisted of soldiers from the British Army's Ulster Defence Regiment (UDR), police officers from the Royal Ulster Constabulary (RUC), and members of the Mid-Ulster Brigade of the Ulster Volunteer Force (UVF). Twenty-five UDR soldiers and RUC police officers were named as purported members of the gang. Details about the group have come from many sources, including the affidavit of former member and RUC officer John Weir; statements by other former members; police, army and court documents; and ballistics evidence linking the same weapons to various attacks. Since 2003, the group's activities have also been investigated by the 2006 Cassel Report, and three reports commissioned by Irish Supreme Court Justice Henry Barron, known as the Barron Reports. A book focusing on the group's activities, Lethal Allies: British Collusion in Ireland, by Anne Cadwallader, was published in 2013. It drew on all the aforementioned sources, as well as Historical Enquiries Team investigations. The book was the basis for the 2019 documentary film Unquiet Graves, directed by Sean Murray.

Ulster loyalism is a strand of Ulster unionism associated with working class Ulster Protestants in Northern Ireland. Like other unionists, loyalists support the continued existence of Northern Ireland within the United Kingdom, and oppose a united Ireland independent of the UK. Unlike other strands of unionism, loyalism has been described as an ethnic nationalism of Ulster Protestants and "a variation of British nationalism". Loyalists are often said to have a conditional loyalty to the British state so long as it defends their interests. They see themselves as loyal primarily to the Protestant British monarchy rather than to British governments and institutions, while Garret FitzGerald argued they are loyal to 'Ulster' over 'the Union'. A small minority of loyalists have called for an independent Ulster Protestant state, believing they cannot rely on British governments to support them. The term 'loyalism' is usually associated with paramilitarism.