William Maxwell Gaines (March 1, 1922 – June 3, 1992), was an American publisher and co-editor of EC Comics. Following a shift in EC's direction in 1950, Gaines presided over what became an artistically influential and historically important line of mature-audience comics. He published the satirical magazine Mad for over 40 years.

He was posthumously inducted into the comic book industry's Will Eisner Comic Book Hall of Fame (1993) and the Jack Kirby Hall of Fame (1997). In 2012, he was inducted into the Ghastly Awards' Hall of Fame.