Philip Barton Key (b:1818, Georgetown, DC - d:27 February 1859, Washington, DC) was the United States Attorney for the District of Columbia, the son of Francis Scott Key, and a murder victim.

In 1859, Congressman Daniel Sickles shot and killed Phillip Barton Key, for having conducted an affair with his wife Teresa. The murder took place on Lafayette Square, just north of the White House. Sickles was acquitted, on the basis of temporay insanity, in one of the most controversial trials of the 19th century.

Key at the time of his death was serving as the United States Attorney for the District of Columbia.