Dame Una Constance Pope-Hennessy DBE (1876–17 August 1949), née Una Constance Birch, was a British writer, mainly on history and biography.
She was the daughter of Sir Arthur Birch and married Major (later Major-General) Richard Pope-Hennessy in 1910.
During the First World War, she was a member of the Central Prisoners of War Committee of the British Red Cross Society. For this work, she was appointed Dame Commander of the Order of the British Empire (DBE) in the 1920 civilian war honours.
Her two sons were both notable in their own right: James Pope-Hennessy was a writer and Sir John Pope-Hennessy an art historian.
Pope-Hennessy's books, usually published as Una Birch, included: