William David Murray, 4th Earl of Mansfield, 3rd Earl of Mansfield KT DL (21 February 1806 – 1 August 1898), was a British Conservative politician. The son of David William Murray, 3rd Earl of Mansfield, and Frederica Markham, daughter of William Markham, Archbishop of York, he succeeded his father in 1840 to the Earldom of Mansfield (1792 creation), and grandmother, Louisa Murray, 2nd Countess of Mansfield, in 1843 as Earl of Mansfield (1776 creation). He was appointed a Knight of the Thistle in 1843 and was for a time Senior Knight.