Harvey Williams Cushing (April 8, 1869 – October 7, 1939) was an American neurosurgeon, pathologist, writer, and draftsman. A pioneer of brain surgery, he was the first exclusive neurosurgeon and the first person to describe Cushing's disease. He wrote a biography of physician William Osler in three volumes.

Cushing was born in Cleveland, Ohio. His parents were Elizabeth Maria "Betsey M." Williams (sister of Edward and Charles Williams) and Henry Kirke Cushing, a physician whose ancestors came to Hingham, Massachusetts, as Puritans in the 17th century. Harvey, the fourth generation of a line of physicians founded by his great-grandfather Dr. David Cushing (1768–1814), was the youngest of ten children.

As a child, Cushing attended the Cleveland Manual Training School, which expanded his interest in science and medicine. The school's emphasis on experimental training and a "physics-focused" approach to education played an important role in influencing Cushing toward a career in medical surgery. The school's manual dexterity training program also contributed to Cushing's future success as a surgeon.

He graduated with an B.A. degree in 1891 from Yale University, where he was a member of Scroll and Key and Delta Kappa Epsilon (Phi chapter). He studied medicine at Harvard Medical School and earned his medical degree in 1895. Cushing completed his internship at Massachusetts General Hospital and then did a residency in surgery under the guidance of pioneering surgeon William Stewart Halsted at the Johns Hopkins Hospital in Baltimore.

He subsequently trained in neurological surgery abroad under Emil Theodor Kocher at Bern and Charles Scott Sherrington at Liverpool.

Cushing began his career in private practice in Baltimore. During his time with Kocher, he first encountered the Cushing reflex, which describes the relationship between blood pressure and intracranial pressure. At the age of 32, he was made associate professor of surgery at Johns Hopkins Hospital and was placed in full charge of cases of surgery of the central nervous system. He wrote numerous monographs on surgery of the brain and spinal column and made important contributions in bacteriology. He conducted (with Kocher) a study of intracerebral pressure and (with Sherrington) contributed much to the localization of the cerebral centers.

In Baltimore, he developed the method of operating with local anesthesia, and his paper on its use in hernia gave him a European reputation. In 1911, he was appointed surgeon-in-chief at the Peter Bent Brigham Hospital in Boston. He became a professor of surgery at the Harvard Medical School starting in 1912. In 1913, he was made an honorary F.R.C.S. (London). He was elected a Fellow of the American Academy of Arts and Sciences in 1914. In 1915, before the Clinical Congress of Surgeons in Boston, he showed the possibility of influencing stature by operating on the pituitary gland. In 1924, Cushing was awarded the Cameron Prize for Therapeutics of the University of Edinburgh.

Shortly after the entry of the United States into World War I, Cushing was commissioned as a major in the U.S. Army Medical Corps on May 5, 1917. He was director of the U.S. base hospital attached to the British expeditionary Force in France. Cushing also served as the head of a surgical unit in a French military hospital outside of Paris. During his time at the French military hospital, Cushing experimented with the use of electromagnets to extract metallic shrapnel fragments that were lodged within the brain. He was mentioned in a dispatch by Field Marshal Sir Douglas Haig in November 1917.