Overall, Duck Soup received a critical drubbing upon its November 17, 1933 release, a reputation that has since turned 180 degrees in the opposite direction.

Motion Picture Herald took a chance when it praised Duck Soup, calling it "another truckload of hilarious nonsense from the irrepressible comedy four," while Variety noted that "practically everybody wants a laugh right now and Duck Soup should make practically everybody laugh."

Alas, the Variety critic's prediction did not prove true. The New York Times thought Duck Soup was "extremely noisy without being nearly as mirthful as their other films." Time said it was no different from their other films, while Nation informed the reader, "Pretty near everyone seems to have agreed that in Duck Soup the Four Marx Brothers are not quite so amusing." Nation elaborated by saying that Harpo comes off as "tiresome," Groucho is "badly provided for," and Chico and Zeppo have "less excuse than usual for their existence." Ouch. New Republic and New Statesman, intellectual publication that supposedly embraced the Marx Brothers' anarchic brand of comic mayhem, were painfully silent about Duck Soup.

Meanwhile, the Los Angeles Times declared "the same tricks can't be worked over and over again. The comedy quartet has a rather set routine." And as the New York Sun bluntly put it, the Marxes had taken "something of a nose dive" with Duck Soup.

As for the film's 180 degrees about-face, Duck Soup started to generate a cult following after college campuses, film festivals, and museums, such as the Museum of Modern Art, started to show it and other Marx Brothers in revival screenings. It is now considered to be the Marx Brothers' masterpiece.

British critic Patrick McCray has said that "as an absurdist essay on politics and warfare, Duck Soup can stand alongside (or even above) the works of Beckett and Ionesco."

Comedian and filmmaker Woody Allen, who owes more than his fair share of debt to the Marx Brothers, said at one time, "If you were asked to name the best comedies ever made, and you named The Gold Rush (1925) and The General (1927) and a half dozen others, Duck Soup is the only one that doesn't have a dull spot."

In 1990, Duck Soup got the last laugh on all of its dullard contemporary critics when it was placed on the revered list of preserved treasures from the National Registry of Historic Films.