John Marshall Harlan was an American lawyer and jurist who served as an associate justice of the U.S. Supreme Court from 1955 to 1971. Harlan is usually called John Marshall Harlan II to distinguish him from his grandfather, John Marshall Harlan, who served on the U.S. Supreme Court from 1877 to 1911.

John Marshall Harlan was an American lawyer and politician who served as an associate justice of the Supreme Court of the United States from 1877 until his death in 1911. He is often called "The Great Dissenter" due to his many dissents in cases that restricted civil liberties, including the Civil Rights Cases, Plessy v. Ferguson, and Giles v. Harris. Many of Harlan's views expressed in his notable dissents would become the official view of the Supreme Court starting from the 1950s Warren Court and onward.