William Richard George Stanley, 9th Earl of Derby, styled Lord Strange from 1655 to 1672, was an English peer.
Derby was the eldest son of Charles Stanley, 8th Earl of Derby, and Dorotha Helena Kirkhoven. He succeeded his father in the earldom in 1672 and later served as Lord Lieutenant of Lancashire from 1676 to 1687 and again from 1688 to 1701 and of Cheshire from 1676 to 1687. Lord Derby married Lady Elizabeth Butler, daughter of Thomas Butler, Earl of Ossory, in 1673. His only son James Stanley, Lord Strange, predeceased him. On his death in November 1702 his junior title of Baron Strange fell into abeyance between his two daughters (it was later called out abeyance in favour of the eldest daughter, Henrietta). He was succeeded in the earldom by his younger brother James Stanley, 10th Earl of Derby. Lady Derby died in 1717.