James S. Harlan (November 24, 1861 – September 20, 1927) was an American lawyer and commerce specialist, son of U.S. Supreme Court Justice John Marshall Harlan and uncle of Justice John Marshall Harlan II.
Harlan was born at Evansville, Indiana, graduated from Princeton University in 1883, and studied law in the office of Melville W. Fuller in 1884 to 1888. Admitted to the bar in 1886, he practiced law in Chicago as a member of the firms of Gregory, Booth, and Harlan, and Harlan and Harlan. From October 1888 to 1889, he served as the first law clerk to Chief Justice Fuller.
In 1901, President Theodore Roosevelt nominated Harlan as Attorney General of Puerto Rico and he served until 1903. He became a member in 1906, and chairman in 1914, of the United States Interstate Commerce Commission.
In 1897, he married Mary Maud Noble in Washington, D.C.