Jack Allan Abramoff ( born February 28, 1959) is an American lobbyist, businessman, film producer, writer, and convicted felon. He was at the center of an extensive corruption investigation led by Earl Devaney that resulted in his conviction and 21 other people either pleading guilty or being found guilty, including White House officials J. Steven Griles and David Safavian, U.S. Representative Bob Ney, and nine other lobbyists and congressional aides. Abramoff was College Republican National Committee National Chairman from 1981 to 1985, a founding member of the International Freedom Foundation, allegedly financed by apartheid South Africa, and served on the board of directors of the National Center for Public Policy Research, a conservative think tank. From 1994 to 2001 he was a top lobbyist for the firm of Preston Gates & Ellis, and then for Greenberg Traurig until March 2004.

After a guilty plea in the Jack Abramoff Native American lobbying scandal and his dealings with SunCruz Casinos in January 2006, he was sentenced to six years in federal prison for mail fraud, conspiracy to bribe public officials, and tax evasion. He served 43 months before being released on December 3, 2010. After his release from prison, he wrote the autobiographical book Capitol Punishment: The Hard Truth About Washington Corruption From America's Most Notorious Lobbyist which was published in November 2011.

Abramoff's lobbying and the surrounding scandals and investigation are the subject of two 2010 films: the documentary Casino Jack and the United States of Money, released in May 2010, and the feature film Casino Jack, released on December 17, 2010, starring Kevin Spacey as Abramoff.