John Hart Ely (December 3, 1938 - October 25, 2003) is one of the most widely-cited legal scholars in United States history, ranking just after Richard Posner, Ronald Dworkin, and Oliver Wendell Holmes, Jr., according to a 2000 study in the University of Chicago's Journal of Legal Studies.

He was born in New York City, and graduated from Princeton and Yale Law School. As a summer clerk at Arnold, Fortas & Porter, a Washington, D.C. law firm, he assisted Abe Fortas in the landmark case of Gideon v. Wainwright (1961), writing a first draft of a brief on behalf of Clarence Earl Gideon, a Florida drifter who had been tried and convicted without a lawyer, who, as recounted in the famous book Gideon's Trumpet, scrawled his petition for Habeas Corpus from a prison cell in his own handwriting. The Supreme Court ruled in Gideon's favor. Ely served as the youngest staff member of the Warren Commission, which investigated the assassination of President John F. Kennedy. He went on to clerk for Chief Justice Earl Warren on the Supreme Court, whom he considered a hero, and to whom he dedicated his landmark book, Democracy and Distrust (1980).

Joining the faculty of Yale Law School in 1968, and moving to Harvard Law School in 1973, Ely wrote several influential law review articles, including a devastating critique of the Supreme Court's decision in Roe v. Wade in an article entitled "The Wages of Crying Wolf," published in the Yale Law Review , wherein he argued that the Court's decision protecting abortion rights was wrong "because it is not constitutional law and gives almost no sense of an obligation to try to be."

Ely's most notable work, however, was his 1980 book Democracy and Distrust, which ranks as one of the most influential works about Constitutional law ever written. In it, he argues against "interpretivism," of which Hugo Black was an exponent, and "originalism," advanced by Justices such as Antonin Scalia, by contending that "strict construction" fails to do justice to the open texture of many of the Constitution's provisions; at the same time, though, he maintains that the notion that judges may infer broad moral rights and values from the Constitution is radically undemocratic. Instead, Ely argued that the Supreme Court should interpret the Constitution so as to reinforce democratic processes and popular self-government, by ensuring equal representation in the political process (as in the Court's decision in Baker v. Carr [1961]).

He went on to serve as dean of Stanford Law School from 1982 to 1987, and remained on the faculty until 1996. Prompted by his love of scuba diving, he moved to the University of Miami School of Law in 1996 and was on its faculty when he died of cancer.

He was married to Gisela Cardonne Ely, who is a state judge in Miami.