Mary Louise Petty (January 4, 1916 – September 14, 2001) was an American army nurse during World War II.

Petty was born in Seattle, Washington and raised in Chicago, where she graduated from Wendell Phillips High School.

[2][3] Petty was the first Black member of the U.S. Army Nurse Corps to achieve the rank of captain.

[4][5] In early 1944 she was assigned to head a training center for Black nurses at Fort Huachuca, Arizona.

[10] Mary L. Petty gave an interview in 2001 to the Chicago Tribune, about her "mostly fond memories" of being an Army nurse; at the time she was described as "nearly blind and suffering from depression and other maladies".