The Household Cavalry (HCAV) is a corps of the Household Division that is made up of the two most senior regiments of the British Army – The Life Guards and The Blues and Royals (Royal Horse Guards and 1st Dragoons). They have taken part in every major conflict since 1660. These regiments are divided between the Household Cavalry Regiment stationed at Wing Barracks in Wiltshire, with an armored reconnaissance role, and the ceremonial mounted unit, the Household Cavalry Mounted Regiment, garrisoned at Hyde Park Barracks in London. Both the HCMR and HCR are made up of elements of the Life Guards and the Blues and Royals. The Household Cavalry is part of the Household Division and is the King's official bodyguard. Although the Household Cavalry Regiment is armoured, it is not part of the Royal Armoured Corps, being assigned to the Household Division.

The Household Cavalry is classed as a corps in its own right, and consists of two regiments: The Life Guards and The Blues and Royals (Royal Horse Guards and 1st Dragoons). They are the senior regular regiments in the British Army, with traditions dating from 1660, and act as the King's personal bodyguard. They are the cavalry element of the guards regiments and, with the five foot guard regiments, constitute the seven guards regiments of the Household Division.

Below is the structure of the regiment:

The Household Cavalry as a whole is split into two different units that fulfil very distinct roles. These are both joint units, consisting of personnel from both regiments. Like other Cavalry formations, the Household Cavalry is divided into regiments (battalion-sized units) and squadrons (company-sized sub-units). The whole corps is under the command of the Commander Household Cavalry (formerly Colonel Commanding The Household Cavalry), who also holds the Royal Household appointment of Silver Stick in Waiting. He is a Colonel and is assisted by a retired lieutenant colonel as Regimental Adjutant.

The Household Cavalry Regiment (HCR) has an active operational role as a Formation Reconnaissance Regiment, serving in armoured fighting vehicles including the Warrior and Ajax, operating far ahead of the main body of friendly forces. Their role is to locate and report on the movement and disposition of enemy forces, and engage and destroy enemy reconnaissance elements that are seeking to do the same. The regiment forms one of five formation reconnaissance regiments in the British Army's order of battle. The HCR has four operational squadrons, three of which are traditional medium reconnaissance squadrons equipped with the Warrior and Ajax armoured fighting vehicles, and the fourth is referred to as Command and Support Squadron and includes specialists, such as Forward Air Controllers. One of the HCR's squadrons has been assigned to the airborne role, supporting 16 Air Assault Brigade Combat Team, since 2003. The regiment was formerly based at Combermere Barracks, Windsor, one mile from Windsor Castle, until its move to Bulford Camp, Wiltshire, in May 2019. The members of the Household Division have sometimes been required to undertake special tasks as the Sovereign's personal troops. The Household Cavalry were called to Windsor Castle on 20 November 1992 to assist with salvage operations following the 1992 Windsor Castle fire.

The Household Cavalry Mounted Regiment (HCMR) is horsed and carries out mounted (and some dismounted) ceremonial duties on State and Royal occasions. These include the provision of a Sovereign's Escort, most commonly seen on The King's Birthday Parade (Trooping the Colour) in June each year. Other occasions include state visits by visiting heads of state, royal weddings, coronations, or whenever required by the British monarch, including ceremonies associated with the Death and state funeral of Elizabeth II. The regiment also mounts the King's Life Guard at Horse Guards. The HCMR consists of one squadron from The Life Guards, one from The Blues and Royals and a squadron called Headquarters Squadron, which is responsible for all administrative matters and includes the regimental headquarters (RHQ), the Riding Staff, Farriers, Tailors and Saddlers. The Regiment has been based (in various forms) at Hyde Park Barracks, Knightsbridge, since 1795. New troopers and officers are generally first assigned to London upon completion of horsemanship training, referred to, alongside the rest of HCMR personnel, as Mounted Dutymen, and remain there for up to three years. Like the five Foot Guards regiments they rotate between the operational and ceremonial roles.

The Household Cavalry Mounted Regiment provides the King's Life Guard, the mounted guard at the entrance to Horse Guards. Horse Guards is the official main entrance to both St James's Palace and Buckingham Palace. The guard is on horseback from 10 am until 4 pm, with the two sentries changing every hour. From 4 pm until 8 pm, a pair of dismounted sentries remain. At 8 pm, the gates of Horse Guards are locked, and a single sentry remains until 7 am. When the King is in London, the Guard consists of one officer, one corporal major (who carries the standard), two non-commissioned officers, one trumpeter and ten troopers. This is known as a "long guard". When the King is not resident in London, the Guard is reduced to two non-commissioned officers and ten troopers. This is known as a "short guard". Responsibility for mounting the guard alternates between The Life Guards and The Blues and Royals. Every summer, the King's Troop, Royal Horse Artillery takes over the role, while the HCMR conducts important regimental training outside of London.

Second Lieutenants in The Blues and Royals are known as Cornets. Officers also wear different crowns and stars on their badges of rank compared to officers of other regiments. Field officers in the Household Cavalry wear a depiction of the Tudor Crown (referred to in Army Dress Regulations as 'the Imperial Crown') minus the cap, including during the reign of Elizabeth II when field officers in all other regiments wore a depiction of St Edward's Crown. Instead of a depiction of the Bath star, the design used by officers in the Household Cavalry is the Garter star.