Williams’ attorney, Eric Slotegraaf, said in a statement that the soprano died Sunday.
Indiana University Jacobs School of Music spokesman Alain Barker said Williams died of complications from cancer.
The school says Williams became the first African-American female to appear with a major U.S. opera company when she debuted on May 15, 1946, with New York City Opera in the title role of Puccini’s “Madama Butterfly.”
She became the first African-American professor of voice at IU in 1977 and retired in 1997.
Williams was born in Danville, Va., on Oct. 18, 1919, the daughter of a chauffeur. Her grandfather was a singer and choir leader, and by age 8 she was singing in Danville’s Calvary Baptist Church.