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.

Unionism in Ireland is a political tradition that professes loyalty to the crown of the United Kingdom and to the union it represents with England, Scotland and Wales. The overwhelming sentiment of Ireland's Protestant minority, unionism mobilised in the decades following Catholic Emancipation in 1829 to oppose restoration of a separate Irish parliament. Since Partition in 1921, as Ulster unionism its goal has been to retain Northern Ireland as a devolved region within the United Kingdom and to resist the prospect of an all-Ireland republic. Within the framework of the 1998 Belfast Agreement, which concluded three decades of political violence, unionists have shared office with Irish nationalists in a reformed Northern Ireland Assembly. As of February 2024, they no longer do so as the larger faction: they serve in an executive with an Irish republican First Minister.