More than a dozen disabilities groups are planning public protests against the film “Tropic Thunder” because of what the groups say is the film’s overt ridicule of people with mental disabilities, reports The New York Times.

The groups involved in the protest include Arc of the United States, American Association of People With Disabilities, the National Down Syndrome Congress, and Special Olympics.

Timothy P. Shriver, chairman of the Special Olympics, said he and other Special Olympics officials plan to picket in front of the movie’s Los Angeles premiere today. The film spoofs the movie industry and is directed by the comedian Ben Stiller. It is scheduled for release on Wednesday.

The groups object to the film’s repeated use of the term “retard” in referring to a character in the film. But they are holding off on asking for a boycott until their representatives see the film today.

After viewing one such screening last week, however, representatives of the National Down Syndrome Congress promptly advised other advocate groups to expect a film that is offensive enough to justify mass boycotts.

Mr. Stiller and Stacey Snider, chief executive of the DreamWorks unit that is releasing the film, said the movie’s humor was not aimed at disabled people but at the silliness of actors willing to go to any length in advancing their careers. DreamWorks has altered some television advertising but decided not to edit scenes from the movie.

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