The 18th Royal Hussars (Queen Mary's Own) was a cavalry regiment of the British Army, first formed in 1759. It saw service for two centuries, including the First World War before being amalgamated with the 13th Hussars to form the 13th/18th Royal Hussars in 1922.

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.