Ailsa Mellon Bruce (June 28, 1901 – August 25, 1969), born in Pittsburgh, was a prominent socialite and the daughter of the banker and diplomat Andrew W. Mellon. She served from 1921 to 1932 as her father's official hostess during his tenure as United States Secretary of the Treasury, and again when he was U.S. Ambassador to the United Kingdom in 1932-33.