Sack is a surname. Notable people with the surname include:
Brian Sack, American actor and humorist
Erna Sack, German opera singer (soprano)
John Sack, American journalist
Karl Sack, (1896-1946), German jurist and member of the anti-Nazi resistance movement in World War II
Peter Sack, German shot putter
Robert D. Sack, American judge
Robert L. Sack, American physician
Steve Sack, American editorial cartoonist
Fictional characters:
Johnny Sack, character in The Sopranos