A Night at the Opera is a 1935 American comedy film starring the Marx Brothers (Groucho, Harpo and Chico), and featuring Kitty Carlisle, Allan Jones, Margaret Dumont, Sig Ruman, and Walter Woolf King. It was the first of five films the Marx Brothers made under contract for Metro-Goldwyn-Mayer after their departure from Paramount Pictures, and the first after Zeppo left the act. The film was written by George S. Kaufman and Morrie Ryskind from a story by James Kevin McGuinness, with additional uncredited dialogue by Al Boasberg. The film was directed by Sam Wood.

One of MGM's biggest hits at the 1935 box office, A Night at the Opera was selected in 1993 for preservation in the National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant". It is also included in the 2007 update of AFI's 100 Years... 100 Movies, at number 85; and previously in AFI's 100 Years...100 Laughs 2000 showing, at number 12.