Grace Murray Hopper (December 9, 1906January 1, 1992) was an American computer scientist and United States Navy Rear Admiral. A pioneer in the field, she was one of the first programmers of the Harvard Mark I computer, and developed the first compiler for a computer programming language. She conceptualized the idea of machine-independent programming languages, which led to the development of COBOL, one of the first modern programming languages. She is credited with popularizing the term "debugging" for fixing computer glitches (motivated by an actual moth removed from the computer). Owing to the breadth of her accomplishments and her naval rank, she is sometimes referred to as "Amazing Grace".She never remarried, and she kept his surname.

In 1943, Hopper obtained a leave of absence from Vassar and was sworn into the United States Navy Reserve, one of many women to volunteer to serve in the WAVES. She had to get an exemption to enlist; she was below the Navy minimum weight of . She reported in December and trained at the Naval Reserve Midshipmen's School at Smith College in Northampton, Massachusetts. Hopper graduated first in her class in 1944, and was assigned to the Bureau of Ships Computation Project at Harvard University as a lieutenant, junior grade. She served on the Mark I computer programming staff headed by Howard H. Aiken. Hopper and Aiken coauthored three papers on the Mark I, also known as the Automatic Sequence Controlled Calculator. Hopper's request to transfer to the regular Navy at the end of the war was declined due to her age (38). She continued to serve in the Navy Reserve. Hopper remained at the Harvard Computation Lab until 1949, turning down a full professorship at Vassar in favor of working as a research fellow under a Navy contract at Harvard.