Agnes Keyser, DStJ, RRC (July 1852 – 11 May 1941) was a humanitarian, courtesan and longtime mistress to Edward VII, King of the United Kingdom.
Keyser was the wealthy daughter of a Stock Exchange member, and of all of Edward VII's mistresses, with the exception of socialite Jennie Jerome, she was the best accepted within royal circles, including by King Edward's wife, Alexandra of Denmark.
She remained with the King until his death in 1910.
Keyser, as recorded by author Raymond Lamont-Brown in his book Edward VII's Last Loves: Alice Keppel and Agnes Keyser, held an emotional bond with the King that others did not, due to her being unmarried herself, and preferring a more private affair to that of a public one.
Keyser was born Elizabeth Agnes Keyser in July 1852 at Great Stanmore in Middlesex, the daughter of Charles and Margaret Keyser.
Her father was a partner in a stock exchange firm Ricardo and Keyser.
She died at Buckland House, Farringdon, Berkshire on 11 May 1941, aged 88.