The Pentagon Papers, officially titled Report of the Office of the Secretary of Defense Vietnam Task Force, is a United States Department of Defense history of the United States' political and military involvement in Vietnam from 1945 to 1967. Released by Daniel Ellsberg, who had worked on the study, they were first brought to the attention of the public on the front page of The New York Times in 1971. A 1996 article in The New York Times said that the Pentagon Papers had demonstrated, among other things, that the Johnson Administration had "systematically lied, not only to the public but also to Congress."

The Pentagon Papers revealed that the U.S. had secretly enlarged the scope of its actions in the Vietnam War with coastal raids on North Vietnam and Marine Corps attacks—none of which were reported in the mainstream media. For his disclosure of the Pentagon Papers, Ellsberg was initially charged with conspiracy, espionage, and theft of government property; charges were later dismissed, after prosecutors investigating the Watergate scandal discovered that the staff members in the Nixon White House had ordered the so-called White House Plumbers to engage in unlawful efforts to discredit Ellsberg. In June 2011, the documents forming the Pentagon Papers were declassified and publicly released.