John Hart Ely ( EE-lee; December 3, 1938 – October 25, 2003) was an American legal scholar. He was a professor of law at Yale Law School from 1968 to 1973, Harvard Law School from 1973 to 1982, Stanford Law School from 1982 to 1996, and at the University of Miami Law School from 1996 until his death. From 1982 until 1987, he was the 9th dean of Stanford Law School.

As a third-year student at Yale Law School, Ely became a member of the legal team of Abe Fortas, contributing to the landmark ruling in Gideon v. Wainwright that required states to provide legal representation to those who could not afford their own. He continued his legal career as the youngest staff member of the much-scrutinized Warren Commission tasked with investigating the assassination of John F. Kennedy. After clerking for Justice Earl Warren, he would go on to study abroad and returned to take a modest position as a public defender before beginning a distinguished career in academia as a professor at Yale, Harvard, and Stanford.

During his scholarly career, Ely became known for his witty legal writing, devotion to the separation of powers, and championship of the political process theory. An outspoken critic of judicial activism, he penned an article in the pages of the Yale Law Journal criticizing the Supreme Court's decision in Roe v. Wade in spite of his own agreements with the ruling on policy grounds. His 1980 work, Democracy and Distrust, became the most-cited legal text written in the 20th century.

In 1996, Ely had three publications which were among the most-cited law review articles of all time. According to a 2000 study in the University of Chicago's Journal of Legal Studies, he was one of the most widely-cited legal scholars in American history having been ranked just after Richard Posner, Ronald Dworkin, and Oliver Wendell Holmes Jr.