1st The Queen's Dragoon Guards (QDG) is a cavalry regiment of the British Army. Nicknamed The Welsh Cavalry, the regiment recruits from Wales, Herefordshire, and Shropshire, and is the senior cavalry regiment, and therefore senior regiment, of the line of the British Army. The regiment is part of the Royal Armoured Corps.

The current regiment was formed in 1959 by the amalgamation of 1st King's Dragoon Guards (raised in 1685 as Lanier's or 2nd Queen's Regiment of Horse by James II of England in reaction to the Monmouth Rebellion) and the Queen's Bays or 2nd Dragoon Guards (the former Peterborough's or 3rd Regiment of Horse, also raised in 1685 by James II in reaction to the Monmouth Rebellion). In 1896 Emperor Franz Joseph of Austria was appointed Colonel-in-Chief of the 1st King’s Dragoon Guards and allowed the regiment to wear the Austrian imperial coat of arms, which is still used as the regiment's cap badge today. Also the regiment adopted an Austrian military march, Radetzky March, as quick march. The regimental museum is located in Cardiff Castle.