The 1921 Northern Ireland general election was held on Tuesday, 24 May 1921. It was the first election to the Parliament of Northern Ireland. Ulster Unionist Party members won a two-thirds majority of votes cast and more than three-quarters of the seats in the assembly. Sinn Féin in particular was shocked at the scale of the Unionist victory, having spent considerable resources on the campaign, and had expected to win between 1/3 and 1/2 of the seats. Sinn Féin and Nationalist Party candidates were successful in the joint County Tyrone/Fermanagh constituency with 54.71 percent of the vote. The election was conducted using the single transferable vote system.

The Parliament of Northern Ireland was the home rule legislature of Northern Ireland, created under the Government of Ireland Act 1920, which sat from 7 June 1921 to 30 March 1972, when it was suspended because of its inability to restore order during The Troubles, resulting in the introduction of Direct Rule. It was abolished under the Northern Ireland Constitution Act 1973.