The Royal Armouries Museum in Leeds, West Yorkshire, England, is a national museum that holds the National Collection of Arms and Armour. It is part of the Royal Armouries family of museums, with other sites at the Royal Armouries' traditional home in the Tower of London, and the National Collection of Artillery at Fort Nelson, Hampshire. The Royal Armouries is a non-departmental public body sponsored by the Department for Culture, Media and Sport.

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