The Royal Armouries is the United Kingdom's national collection of arms and armour. Once an important part of England's military organization, it became the United Kingdom's oldest museum, and one of the oldest museums in the world. It is also one of the largest collections of arms and armour in the world, comprising the UK's National Collection of Arms and Armour, National Artillery Collection, and National Firearms Collection. Originally housed in the Tower of London from the 15th century, today the collection is split across three sites: the Tower, the Royal Armouries Museum in Leeds, and Fort Nelson near Portsmouth

Armour or armor is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or from a potentially dangerous environment or activity. Personal armour is used to protect soldiers and war animals. Vehicle armour is used on warships, armoured fighting vehicles, and some combat aircraft, mostly ground attack aircraft.