Sir John Walter Buchanan-Riddell, 11th Baronet (14 March 1849 – 31 October 1924) was a British barrister and baronet. He was educated at Eton College and Christ Church, Oxford before being called to the bar (becoming a barrister) by Inner Temple in 1874. He succeeded his uncle as 11th Baronet in the line of Riddell Baronets in 1892. In 1897, he served as High Sheriff of Northumberland. He was a member of the Council of Keble College, Oxford from 1899 until his death. He died on 31 October 1924, succeeded by his son, Sir Walter Robert Buchanan-Riddell, 12th Baronet, who was Principal of Hertford College, Oxford.