Elizabeth Pakenham, Countess of Longford, CBE (née Harman; 30 August 1906 – 23 October 2002), better known as Elizabeth Longford, was a British historian. She was a member of the Royal Society of Literature and was on the board of trustees of the National Portrait Gallery in London. She is best known as a historian, especially for her biographies of 19th-century luminaries such as Queen Victoria (1964), Lord Byron (1976) and the Duke of Wellington (2 vol 1969).
The daughter of eye specialist Nathaniel Bishop Harman, she was educated at the Francis Holland School, and was an undergraduate at Lady Margaret Hall, Oxford. "Able, articulate and beautiful", in the words of The New York Times, she was "the Zuleika Dobson of her day, with undergraduates and even dons tumbling over one another to fall in love with her". A few years after her graduation, on 3 November 1931, she married Frank Pakenham, later 7th Earl of Longford, who died in August 2001. Her obituary by the BBC said the marriage was "famously harmonious." The New York Times, in its review of The Pebbled Shore, called Lady Longford "easily the best writer in what is predominantly a literary family".
She and her husband were both devout Roman Catholic converts, Lady Longford having been raised a Unitarian, and avid social reformers. The Longfords had eight children, among them the writers Lady Antonia Fraser, Lady Rachel Billington, Judith Kazantzis, and Thomas Pakenham.