The Musical Mutual Protective Union (MMPU) was a New York union of musicians, formed in 1863, with a focus on payment made to musicians in theaters and at balls.

[1][2][3] In 1885, the union was open to "all instrumental performers, who have been residents of the United States for the period of six months previous to application.

"[4] Foreign musicians were not allowed to play in orchestras unless they were in a union.

[2][6] In 1910, approximately 300 black musicians were members in the roughly 8,000-member union.

[5] In 1929 the union planned a mass march against joblessness, claiming 35,000 unemployed, but was unable to secure a parade permit from the police.