The Anglo-Irish Agreement was a 1985 treaty between the United Kingdom and the Republic of Ireland which aimed to help bring an end to the Troubles in Northern Ireland. The treaty gave the Irish government an advisory role in Northern Ireland's government while confirming that there would be no change in the constitutional position of Northern Ireland unless a majority of its people agreed to join the Republic. It also set out conditions for the establishment of a devolved consensus government in the region.

The Agreement was signed on 15 November 1985, at Hillsborough Castle, by British Prime Minister Margaret Thatcher and Irish Taoiseach (prime minister) Garret FitzGerald.