The original stage version of Maria's song "I Feel Pretty" included the lyrics "I feel pretty and witty and bright / And I pity / Any girl who isn't me tonight." In the film this night scene was changed to the daytime, and presumably for this reason, the rhyming words "bright" and "tonight" were changed to "gay" and "today
Rita Moreno's singing voice was dubbed by Betty Wand only for "A Boy Like That" since it was below her range. Moreno sang "America" and "Quintet" herself
Betty Wand sued to get a percentage of the movie-album sales, having dubbed part of Rita Moreno's singing. The dispute was settled out-of-court
Film rights to the play were bought for $375,000.
Six members of the original Broadway cast appeared in the movie: Carole d'Andrea (Velma), David Winters (movie: A-Rab, Broadway: Baby John), Jay Norman (movie: Pepe, Broadway: Juano), Tommy Abbott (Gee-Tar), Tony Mordente (movie: Action, Broadway: A-Rab), William Bramely (Officer Krupke)
Robert Wise's original choice to play Tony was Elvis Presley.
Most of the original Broadway cast were rejected for the film as either photographing or actually being too old for the teen-aged characters. And since Hollywood was accustomed to dubbing the singing voices of many stars, dozens of non-singing actors and actresses were tested or considered for the leading roles. Among them: Suzanne Pleshette, Jill St. John, Audrey Hepburn, Anna Maria Alberghetti, Elizabeth Ashley, Anthony Perkins, Warren Beatty, Bobby Darin, Burt Reynolds, Richard Chamberlain, Troy Donahue and Gary Lockwood.
Audrey Hepburn was offered the role of Maria, but she turned it down, because she was pregnant with Sean H. Ferrer at the time.
Throughout the movie, Natalie Wood wears a bracelet on her left wrist, not for any esthetic reason, but because she had injured her wrist on the set of a previous movie, causing an unsightly bone protrusion on her wrist. She wore the bracelet to hide the injury.
"To be yourself in a world that is constantly trying to make you something else is the greatest accomplishment.
Ralph Waldo Emerson