Walker, Mary Edwards (1832–1919), a United States physician and women's rights crusader. She was one of the first female physicians in the United States, the first female surgeon in the U.S. Army, and the only woman to win the Medal of Honor.

Walker was born in Oswego, New York. Overcoming prejudice against female medical students, she got her degree at Syracuse Medical College in 1855. During the Civil War, she worked as a nurse until she was able to obtain appointment as an assistant surgeon, in 1863. In 1865 Walker was awarded the Medal of Honor for meritorious service. Following the war, she devoted much of her time to promoting woman suffrage and other causes.

In 1917 a federal board revoked Walker's medal along with those of many others for not having been won in combat. The award was reinstated by the U.S. Army in 1977.