Mildred Couper (December 10, 1887 in Buenos Aires, Argentina – August 9, 1974[1] in Santa Barbara, United States) was a prominent composer and pianist, and one of the first American musicians to experiment with quarter-tone music.

She moved with her children to California in 1927 and established a studio in Santa Barbara, where she started her experiments with two pianos by tuning the first a quarter tone higher than the second.

Mildred Couper also wrote incidental music for plays at the Lobero and also a dance-opera, And on Earth Peace, with libretto by Scottish-Argentine artist Malcolm Thurburn.

[7] Mildred Cooper married American expatriate artist Richard Hamilton Couper in 1910, and they had two children, Clive (1913-2004) and Rosalind (1915-2016), both born in Rome.

[8] Mildred Cooper's first cousin Harry Norman Jacobs (1877-1951) was the grandfather of Argentine-born composer Carlos Micháns(-Jacobs) (1950-), who resides in the Netherlands since 1982.