Oopsla! is a science fiction fanzine by Gregg Calkins.
Contributors included Ron Bennett (Ploy), John Berry (Pot Pourri), Robert Bloch, Vernon L. McCain (Wastebasket), with his column, "The Mark Of McCain", Wilson "Bob" Tucker (Le Zombie), Harry Warner, Jr. (Horizons), and Walt Willis (Hyphen), with his column, "The Harp That Once Or Twice".
The article "Bah! Humbug!" written by Robert Bloch for Oopsla! was included in the fanzine yearbook, The Best of Fandom 1958.