Dudley Francis Stuart Ryder, 3rd Earl of Harrowby PC JP DL (16 January 1831 – 26 March 1900), known as Viscount Sandon from 1847 to 1882, was a British peer and politician.

On his return to England, he did garrison duty as captain in the 2nd Staffordshire militia regiment, during the Crimean War and Indian mutiny.

He gained experience of affairs as private secretary to Henry Labouchere at the colonial office.

[1] He was a member of the select committees on the Hudson's Bay Company (1857) and the Euphrates Valley (1871–72), and continued throughout life to devote much time and attention to the study of imperial and colonial questions.

[1] He was Vice-President of the Committee on Education from 1874 to 1878, and President of the Board of Trade (with a seat in the cabinet) from 1878 to 1880 in Benjamin Disraeli's second administration and was sworn of the Privy Council in 1874.