Mortimer Sackville-West, 1st Baron Sackville (22 September 1820 – 1 October 1888), was a British peer and court official. Sackville-West was the fourth son of George Sackville-West, 5th Earl De La Warr, and Elizabeth Sackville, 1st Baroness Buckhurst, younger daughter and co-heir of John Sackville, 3rd Duke of Dorset. On the death of his kinsman Charles Sackville-Germain, 5th Duke of Dorset, in 1843, the dukedom and its subsidiary titles became extinct. Large parts of the Sackville estates passed to the West family through Elizabeth. The Sackville-Wests inherited parts of the estates by arrangement, notably the estate of Knole Park in Kent.