The 9th Queen's Royal Lancers was a cavalry regiment of the British Army, first raised in 1715. It saw service for three centuries, including the First and Second World Wars. The regiment survived the immediate post-war reduction in forces, but was amalgamated with the 12th Royal Lancers to form the 9th/12th Royal Lancers in 1960.

There are 13 cavalry Regiments of the British Army each with its own unique cap badge, regimental traditions, and history. Of the currently nine regular cavalry regiments, two serve as armoured regiments, three as armoured cavalry regiments, three as light cavalry, and one as a mounted ceremonial regiment. There are also four yeomanry regiments of the Army Reserve, of these, three serve as light cavalry and one as an armoured regiment. Each yeomanry light cavalry unit has been paired with a regular unit of the same role, the armoured yeomanry unit is paired with the two regular armoured units. All except the Household Cavalry are part of the British Army's Royal Armoured Corps.