American composer, arranger, conductor, and teacher (born December 16, 1925 - died December 24, 2023).
Many of her early arrangements were done in cooperation with Robert Shaw.

She has authored five operas, eleven song-cycles, thirty-three cantatas, eleven works for chorus and orchestra, forty-seven choral suites, and more than forty hymns, all original compositions. Also to be noted are wealth of arrangements based on pre-existing folk-songs and hymns, many of which were produced in collaboration with Robert Shaw. Parker is best known for these kinds of arrangements of spirituals, mountain hymns, and folk songs, early-American hymns, and international folk-songs, most notably in French, Spanish, Hebrew, and Ladino.