A. Mercer Daniel (May 27, 1887 – February 17, 1976) was an American law librarian and the first African American member of American Association of Law Libraries. He worked as a librarian for the United States Department of War, and later went on to serve as a librarian for the Howard University School of Law for more than thirty-five years. Daniel worked to oppose racial discrimination throughout his career and was an activist before and during the civil rights movement.