The Warrenpoint ambush, also known as the Narrow Water ambush, the Warrenpoint massacre or the Narrow Water massacre, was a guerrilla attack by the Provisional Irish Republican Army (IRA) on 27 August 1979. The IRA's South Armagh Brigade ambushed a British Army convoy with two large roadside bombs at Narrow Water Castle outside Warrenpoint, Northern Ireland. The first bomb was aimed at the convoy itself, and the second targeted the incoming reinforcements and the incident command point (ICP) set up to deal with the incident. IRA volunteers hidden in nearby woodland also allegedly fired on the troops, who returned fire. The castle is on the banks of the Newry River, which marks the border between Northern Ireland and the Republic of Ireland.

The Provisional Irish Republican Army, officially known as the Irish Republican Army and informally known as the Provos, was an Irish republican paramilitary force that sought to end British rule in Northern Ireland, facilitate Irish reunification and bring about an independent republic encompassing all of Ireland. It was the most active republican paramilitary group during the Troubles. It argued that the all-island Irish Republic continued to exist, and it saw itself as that state's army, the sole legitimate successor to the original IRA from the Irish War of Independence. It was designated a terrorist organisation in the United Kingdom and an unlawful organisation in the Republic of Ireland, both of whose authority it rejected.