Mary Margaret (Peggy) Cass (May 21, 1924 - March 8, 1999) was an Academy Award-nominated actress, comedian, game show panelist, and announcer.

A native of Boston, Massachusetts, Cass became interested in acting as a member of the drama club at Cambridge Latin School; however, she attended all of high school without a speaking part. After graduating high school, she spent most of the 1940s in search of an acting career, eventually landing Jan Sterling's role in a traveling production of Born Yesterday.

Mary Margaret Cass was born May 21, 1924, in Boston, Massachusetts. After three years in the Cambridge Latin School drama club without one speaking part, she moved to New York, where she worked as a secretary, telephone operator, advertising solicitor and model. She joined a USO troupe that took her to Australia for seven months, but she did not appear in any shows (the U.S. troops had moved on). As understudy, she took Jan Sterling's part in a national tour of "Born Yesterday," finally being cast in her own right in the 1949 Broadway musical "Touch and Go." The mid 1950s brought her the defining role of Agnes Gooch in "Auntie Mame," her stage and screen performances earning her a Tony and an Oscar nomination, respectively. From then on, she was best known for her regular television quiz show appearances: "Keep Talking" (1958), "Match Game 73" (1973), "Password" (1961), and "To Tell the Truth" (1956). She was very smart and very funny, but her signature was her unmistakably raspy voice. She died on March 8, 1999, at Manhattan's Sloane-Kettering Hospital of heart failure.