Glenn Edward Greenwald (born March 6, 1967) is an American journalist, author and lawyer. In 2014, he cofounded The Intercept, of which he was an editor until he resigned in October 2020. Greenwald subsequently started self-publishing on Substack.

In 1996, Greenwald founded a law firm concentrating on First Amendment litigation. He began blogging on national security issues in October 2005, when he was becoming increasingly concerned with what he viewed as attacks on civil liberties by the George W. Bush Administration in the aftermath of the September 11 attacks. He became a vocal critic of the Iraq War and has maintained a critical position of American foreign policy.