Countess of Mornington is a title given to the wife of the Earl of Mornington. Women who have held the title include:
Katherine Wellesley-Pole, Countess of Mornington (c.1760-1851) Hyacinthe-Gabrielle Roland (1766–1816) Elizabeth Wellesley, Duchess of Wellington (1820–1904) Diana Wellesley, Duchess of Wellington (1922–2010) Jemma Wellesley, Marchioness of Douro (born 1974)