Gwendolen Mary Fitzalan-Howard (née Constable-Maxwell), Duchess of Norfolk (11 January 1877 – 28 August 1945) was a daughter of Marmaduke Constable-Maxwell, 11th Lord Herries of Terregles, and his wife, Angela (née Fitzalan-Howard). On 5 February 1904, she married her first cousin once removed, the 15th Duke of Norfolk and became Duchess of Norfolk. The couple later had four children:
Upon the death of her father in 1908, she, as the eldest child and daughter, inherited his title as 12th Lady Herries of Terregles.