Ulster Defence Association

The Ulster Defence Association (UDA) is the largest loyalist paramilitary and vigilante group in Northern Ireland. It was formed in September 1971 and undertook a campaign of almost twenty-four years during "The Troubles". It used the name Ulster Freedom Fighters (UFF) when it wished to claim responsibility for attacks—because the two claimed to be separate organisations, the UDA was able to remain legal for over twenty years. The United Kingdom outlawed the "UFF" in November 1973 and the UDA itself was classified as a terrorist group on 10 August 1992.

The UDA's/UFF's declared goal was to defend loyalist areas from attack and to combat Irish republicanism. However, most of its victims were civilians according to the Sutton Index of Deaths. The majority of them were Irish Catholics, killed in what the group called retaliation for attacks on Protestants. High-profile attacks carried out by the group include the Milltown massacre, the Sean Graham bookmakers' shooting, the Castlerock killings and the Greysteel massacre. The UDA/UFF declared a ceasefire in 1994, although sporadic attacks continued until it officially ended its armed campaign in November 2007.

The UDA were often referred to by their Ulster Volunteer Force (UVF) rivals as the "Wombles", derived from the furry fictional creatures, The Wombles.

The UDA's motto is Quis Separabit, which means Who will separate ? in Latin.