Susan Douglas McGreivy (née Gray; October 24, 1939 – November 30, 2019) was an American competition swimmer who represented the United States at the 1956 Summer Olympics in Melbourne, Australia. She competed in the preliminary heats of the women's 400-meter freestyle, and posted a time of 5:16.7.
McGreivy became a lesbian activist and civil rights attorney for the American Civil Liberties Union (ACLU) of Southern California. She had a "leading role" in a range of ACLU gay and lesbian civil rights issues, including a case against the Boy Scouts of America, a defense of the Gay Games against the United States Olympic Committee, and defense of the Norton Sound Eight.