Kerstin Thorborg (May 19, 1896 - April 12, 1970) was a Swedish opera singer. The contralto Kerstin Thorborg was one of the best dramatic Wagnerian singers in the two decades between 1930 and 1950. By all accounts, Thorborg was a magnificent actor with great stage presence. In addition, she was endowed with a beautifully steady and intense tone.