The Ulster Volunteer Force (UVF) is a Northern Ireland loyalist paramilitary group. The current incarnation was formed in May 1966 and named after the UVF of 1912.

The original UVF formed in January 1913 by Edward Carson and James Craig as a militia in the tensions surrounding the potential success of the third Home Rule campaign. Carson and Craig, supported by some English Conservative politicians, threatened to establish a Provisional government in Ulster should the province be included in any Home Rule settlement. Thousands of German rifles were landed at Larne, but the authorities did not intervene. The issue was put on hold by the outbreak of World War I. Many UVF men enlisted, mostly with the British 36th (Ulster) Division. The men suffered heavy casualties in July 1916 during the Battle of the Somme. Northern Ireland was established by the Government of Ireland Act 1920, which many Ulstermen saw as a reward for their loyal service during the war. Certain remnants of the group reformed in 1920 and were used as special constables (B-Specials).

The current UVF formed to oppose the attacks by nationalists in the mid 1960s. The group was concentrated around East Antrim, County Armagh and the Shankill district of Belfast. The murder of a Belfast barman in June 1966 led to the first leader of the group, Augustus 'Gusty' Spence, being arrested and sentenced to 20 years. The UVF is also considered responsible for a series of attacks on utilities installations in 1969. A bomb in a Belfast bar that killed fifteen people in December 1971 is attributed to the UVF as is the murder of the SDLP politician Paddy Wilson in 1972.

The group was proscribed in July 1966, but this was lifted in April 1974 in an effort to bring the UVF into more recognized democratic processess. The UVF spurned the government efforts and a subset of the UVF dubbed the Shankill Butchers demonstrated their feelings. The group was possibly responsible for the bombs in Dublin and Monaghan of May 17, 1974 when 33 people were killed and it was certainly to blame for the October 2, 1974 deaths of twelve civilians as well as a number of other attacks. The group was returned to illegality on October 3 and two days later 26 suspected UVF members were arrested in a series of raids. The men were tried and in March 1977, and they were sentenced to an average of 25 years each. In the 1980s the UVF was greatly reduced by a series of informers, starting in 1983 with Joseph Bennett's information leading to the arrest of fourteen senior figures..

The UVF joined the Combined Loyalist Military Command in 1990 and indicated its acceptance of the moves towards peace. The UVF agreed to a ceasefire in October 1994. More militant members of the UVF broke away in 1996 to form the Loyalist Volunteer Force (LVF). The UVF has been fighting with the LVF since then and in mid 2000 they also clashed with the largest Loyalist group, the Ulster Defence Association (UDA). The overt clash with the UDA ended in December following seven deaths.

The strength of the UVF is uncertain, it peaked in the early 1970s at possibly over 1,000 but its current strength is around 150 activists - those members prepared to carry out its attacks. The UVF weaponry is limited to small arms, with its sporadic bombing efforts being made using stolen mining explosives.

The Red Hand Commandos is an organisation that was established in 1972, but it is so closely linked with the UVF that it is generally regarded as simply a cover name.

The UVF have committed more killings than any other Protestant paramilitary organisation. Although exact figures vary depending on source, the UVF has killed around 400 people (as of 2003). Most of these were Catholic civilians with no connection to the IRA.

The Progressive Unionist Party (PUP) is the political group most closely reflecting the views of the UVF. They have one member in the Northern Ireland Assembly. The Young Citizen Volunteers (YCV) is the youth section of the UVF.