The Royal Commission on Historical Manuscripts (widely known as the Historical Manuscripts Commission, and abbreviated as the HMC to distinguish it from the Royal Commission on the Historical Monuments of England), was a United Kingdom Royal Commission established in 1869 to survey and report on privately owned and privately held archival records of general historical interest. Its brief was "to make inquiry as to the places in which such Manuscripts and Papers were deposited", and to report on their contents. It remained in existence until 2003, when it merged with the Public Record Office to form The National Archives. Although it technically survives as a legal entity, its work is now entirely subsumed into that of The National Archives.
Following the passing of the Public Record Office Act 1838, which made statutory provision for the care of government archives, pressure began to grow for the state to pay attention to privately owned records. Largely on the initiative of Lord Romilly, the Master of the Rolls, the first Royal Commission on Historical Manuscripts was appointed by Royal Warrant dated 2 April 1869. The first Commissioners were Romilly himself (as chairman); the Marquess of Salisbury; the Earl of Airlie; Earl Stanhope; Lord Edmοnd Petty-Fitzmaurice; Sir William Stirling-Maxwell; Charles Russell, President of Maynooth College; George Webbe Dasent; and T.D. Hardy, Deputy Keeper of the Records. They were shortly afterwards joined by George Butler, Bishop of Limerick; and Lord Talbot de Malahide. A new Royal Warrant of 1876 confirmed the appointment of what had effectively become a standing commission; and the Commission's work was extended by further warrants dated 18 December 1897 and 27 March 1919.