The 8th King's Royal Irish Hussars was a cavalry regiment in the British Army, first raised in 1693. It saw service for three centuries including the First and Second World Wars. The regiment survived the immediate post-war reduction in forces, and went on to distinguish itself in the battles of the Korean War, but was recommended for amalgamation in the 1957 Defence White Paper prepared by Duncan Sandys. The regiment was amalgamated with the 4th Queen's Own Hussars, to form the Queen's Royal Irish Hussars in 1958.

The regiment was first raised by Henry Conyngham as Henry Conyngham's Regiment of Dragoons in Derry in 1693, and ranked as the 8th Dragoons. They soldiered at home as part of the Irish Establishment but were deployed to Spain in 1704 to take part in the War of the Spanish Succession.

The regiment took part in a skirmish near Tanarite at which Henry Conyngham was killed: Robert Killigrew took over but was also killed at the Battle of Almansa in April 1707. Under their new colonel, John Pepper, the 8th Dragoons routed a Spanish cavalry regiment at the Battle of Almenar in July 1710, and, according to tradition, took possession of the enemy regiment's crossbelts. This earned the regiment the nickname "Crossbelt Dragoons", borne for many years. The regiment was captured in its entirety at the Battle of Brihuega in December 1710.

The regiment returned home and was disbanded in 1714. It was re-raised again in 1715 and deployed to Scotland as part of the response to the Jacobite rising of 1715 and again for the Jacobite rising of 1745. The regiment then moved back to Ireland, where, in 1751, they were formally titled as the 8th Regiment of Dragoons and numbered for the first time as the 8th Dragoons. In 1775 they received their first title, "The 8th King's Royal Irish Light Dragoons". The regiment was renamed in 1777 for King George III as the 8th (The King's Royal Irish) Regiment of (Light) Dragoons. The regiment was deployed to the Low Countries in 1794 for service in the Flanders Campaign and took part in a skirmish at Bousbecque where they captured the French guns. After being directed by King George III to wear buff accoutrements as an honour, the regiment returned to England in November 1795.

The regiment deployed to South Africa to control the Boers in 1796, then transferred to North Africa and went on to India in 1802 to put down the activities of Daulat Scindia and Yashwantrao Holkar. It fought at the Battle of Laswari in November 1803; Scindia was defeated and Holkar submitted after 3,000 of his men died at Farakhabad in 1805; a peace treaty was signed in January 1806. The regiment then stormed two fortresses belonging to the rebellious Pindaris in September 1812. In 1814, the regiment then took on the Gurkhas, who were seeking to extend the boundaries of Nepal; Colonel Rollo Gillespie was killed in an action at Kalunga: his horse, Black Bob, became a regimental mascot. In 1818, the colonel of the regiment, Sir Banastre Tarleton, received orders that the regiment was to convert to a hussar regiment, retitled the 8th (The King's Royal Irish) Regiment of (Light) Dragoons (Hussars) The regiment returned to England in 1819. The regiment escorted Queen Victoria and Prince Albert on their first visit to Dublin in 1849.

During the Crimean War, the regiment formed part of the Light Brigade. The regiment set sail from Plymouth in early March 1854. Five ships were needed to transport them to the Black Sea. The Echunga, Mary Anne and the Shooting Star left first, followed by the Medora and the Wilson Kennedy on 1 May. The next battle was near the River Alma in September 1854 and the 8th Hussars were awarded the battle honour for a convincing defeat of the enemy. On 28 September, following a report that Russian troops were out in front of Balaklava town, the troop of the 8th, which made up Lord Raglan's escort under Captain Chetwode, was thrown out in skirmishing order. The Horse Artillery then came up and opened fire, causing the Russians to abandon all their wagons and flee from the scene. Some 70 wagons and carts were captured, some only containing small arms ammunition, which was destroyed. The rest of the wagons contained black bread. The troops were allowed to pillage the wagons that did not contain anything of value to the Commissariat. As a result, within a few minutes, the ground was strewn with various pieces of clothing – Hussar uniforms, fur cloaks, and wigs. The carriages were said to belong to the suite of Prince Menshikov. After this engagement until 25 October, the regiment furnished patrols and outpost duties, being billeted close to vineyards and barns containing water, corn, hay and fuel.

In October, Balaklava and the Charge of the Light Brigade took place. It was started when 25,000 Russians tried to capture Balaklava, the British Army's only port, defended by the 93rd Highlanders, some Turks, and the Cavalry Division. Lieutenant Colonel Sherwell led the King's Royal Irish Hussars, forbidding two soldiers to carry their swords in the charge because they had "Disgraced the regiment by smoking in the presence of the enemy". The charge through the crossfire into the mouths of the Russian guns is vividly described by Lieutenant the Hon S Calthorpe, an 8th Hussar ADC.

The pace of our Cavalry increased every moment, until they went thundering along the valley, making the ground tremble beneath them. On they went headlong to death, disregarding aught but the object of their attack. At length they arrived at the guns, their numbers sadly thinned, but the few that remained made fearful havoc amongst the enemy's artillery.