Marjorie Minna Jenkins Pratt, Countess of Brecknock, DBE, GCStJ, JP (28 March 1900 – 24 August 1989) was a British aristocrat, courtier and socialite.

Brecknock was born at 48 Grosvenor Square, Mayfair,[2] the only child of Colonel Atherton Edward Jenkins and his wife, Anna Isabella (née Schoenbrunn), the niece of Sir Ernest Cassel.

She was a cousin (and life-long close friend) of Edwina Ashley, who married Lord Louis Mountbatten, 1st Earl Mountbatten of Burma.

She married John Pratt, Earl of Brecknock, eldest son of John Pratt, 4th Marquess Camden, and his wife, the former Lady Joan Marion Nevill, on 19 October 1920 in St. Margaret's Church, Westminster, London.

She was Lady-in-Waiting to Princess Marina, Duchess of Kent, and Superintendent-in-Charge, St. John's Ambulance Brigade.