The Royal Hospital site contains a small but interesting Museum. The Museum is mostly composed of artefacts left by deceased In-Pensioners and was originally opened in the Great Hall in 1866.
The entrance Hall is dedicated to the memory of the Duke of Wellington, and a variety of objects associated with him are to be seen in it, including six French "Eagles", George Jones' panorama of the Battle of Waterloo (1820) and a portrait of the Duke by John Simpson. There is also a contemporary painting of Queen Elizabeth II by Andrew Festing (1998).
In the Wellington Hall a diorama depicts The Royal Hospital in about 1742. This shows the Royal Hospital as it was when Ranelagh's land had been turned to commercial use and Walpole had acquired the site on the west side. The original water gardens may also be seen.
Leading from the Hall, the gallery contains the main museum displays and exhibitions. Because it is not possible to visit the Long Wards, a reconstruction of a typical berth has been provided. The uniform of a veteran soldier is also displayed. Invalid units of Pensioners were created from 1703, formed from those who were claiming a pension but found fit for duty. Usually disbanded during peacetime there were 66 companies founded by the Royal Hospital when the invalids were converted in ‘Garrison' battalions in 1803.
The collection of medals has been built up from those of deceased In-Pensioners who bequeathed them to the Royal Hospital, and numbers over 2,100.
The Museum also has two major additions. The parade chair, which was presented to Queen Elizabeth II by the Royal Hospital and the Sovereign's Mace which was presented to the Royal Hospital by Queen Elizabeth II in 2002.