Marguerita "Rita" Spencer (December 28, 1892 – May 5, 1993) was a Canadian pianist, organist, composer and educator.
She was born Marguerita MacQuarrie in Glace Bay, Nova Scotia and studied music there and at the Halifax Ladies' College, where she studied organ, piano and cello. She then studied nursing at the Toronto General Hospital, graduating in 1921. In 1922, she married Roy Aubrey Spencer; the couple moved to Saskatoon, where her husband taught engineering at the University of Saskatchewan.