Jack Herer, American author and activist (b. 1939)
Jack Herer (; June 18, 1939 – April 15, 2010), sometimes called the "Emperor of Hemp", was an American cannabis rights activist and the author of The Emperor Wears No Clothes, a book—in 2020 in its fourteenth edition after having been continuously in print for 35 years—frequently cited in efforts to decriminalize and legalize cannabis and to expand the use of hemp for industrial use. Herer also founded and served as the director of the organization Help End Marijuana Prohibition (HEMP).

The Jack Herer Cup created by R. Foreman is held in Amsterdam, Colombia, Las Vegas, Oklahoma City and Thailand each year to honor the Worldwide Cannabis Legalization Movement that Jack Herer helped start.