Abbot Howard "Abbie" Hoffman (November 30, 1936 – April 12, 1989) was an American political and social activist who co-founded the Youth International Party ("Yippies") and was a member of the Chicago Seven. He was also a leading proponent of the Flower Power movement.

As a member of the Chicago Seven, Hoffman was charged with and tried―for activities during the 1968 Democratic National Convention―for conspiring to use interstate commerce with intent to incite a riot and crossing state lines with the intent to incite a riot under the anti-riot provisions of Title X of the Civil Rights Act of 1968.^: 4 Five of the Chicago Seven defendants, including Hoffman, were convicted of crossing state lines with intent to incite a riot;^: 8 all of the convictions were vacated after an appeal and the U.S. Department of Justice declined to pursue another trial.^: 9 Hoffman, along with all of the defendants and their attorneys were also convicted and sentenced for contempt of court by the judge; these convictions were also vacated after an appeal.^: 9

Hoffman continued his activism into the 1970s, and remains an icon of the anti-Vietnam war movement and the counterculture era. He died of an intentional phenobarbital overdose in 1989 at age 52.