Constance Shacklock OBE (16 April 1913 – 29 June 1999) was an English contralto. After more than a decade of roles with the Covent Garden Opera Company, with other companies and on the concert stage, Shacklock performed for six years in The Sound of Music in London as the Mother Abbess. She taught singing at the Royal Academy of Music from 1968 to 1978.