Dudley Francis Stuart Ryder, 3rd Earl of Harrowby, known as Viscount Sandon from 1847 to 1882, was a British peer and politician.

Dudley Ryder, 2nd Earl of Harrowby, KG, PC, FRS, styled Viscount Sandon between 1809 and 1847, was a British politician. He held office under Lord Palmerston as Chancellor of the Duchy of Lancaster in 1855 and as Lord Privy Seal between 1855 and 1858.