The Reavey and O'Dowd killings were two coordinated gun attacks on 4 January 1976 in County Armagh, Northern Ireland. Six Catholic civilians died after members of the Ulster Volunteer Force (UVF), an Ulster loyalist paramilitary group, broke into their homes and shot them. Three members of the Reavey family were shot at their home in Whitecross and four members of the O'Dowd family were shot at their home in Ballydougan. Two of the Reaveys and three of the O'Dowds were killed outright, with the third Reavey victim dying of brain haemorrhage almost a month later.

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.