Royal Archives Online is the catalogue of the archival collections held in the Royal Archives at Windsor Castle.

This catalogue currently contains descriptions of collections from the reigns of George I (1714-1727) to Edward VII (1901-1910), as well as the eighteenth-century papers of the exiled Stuarts, records relating to the Duke of Cumberland (mainly as Captain General of the British Army between 1745 and 1757) and the papers of 2nd Viscount Melbourne (1779-1848).

Royal Archives Online incorporates the contents of the 'Georgian Papers Online' catalogue and includes digitised images of over 250,000 pages of documents, such as personal letters, diaries, account books and records of the Royal Household, dating principally from the reigns of George III, George IV and William IV. A small number of documents from the Victorian and Edwardian periods are also available digitally.