Respected anthropologist James Krippendorf (Richard Dreyfuss) and his wife, Jennifer (Barbara Williams), bring their three children along during their much-enjoyed search in New Guinea for a lost tribe. The search fails, despite the family's best efforts. After Jennifer's death back in the U.S., James falls into academic stagnation, having spent all his foundation grant money raising the children as a single parent. Scheduled to lecture at a college and fearful of being charged with misuse of grant funds, James concocts an imaginary tribe, the Shelmikedmu, using the names of his children as a basis. He later fakes a 16 mm "documentary" film, casting his children as tribe members and superimposing footage of a legitimate New Guinean tribe so as to enhance the illusion.
Anthropologist Veronica Micelli (Jenna Elfman) contacts cable-TV producer Henry Spivey (David Ogden Stiers), forcing James to continue creating fraudulent footage as James' rival Ruth Allen (Lily Tomlin) becomes suspicious. Because he has described a culture unlike any other, Krippendorf's fraud becomes increasingly famous. James himself masquerades as a tribal elder, while his two sons, Mickey (Gregory Smith) and Edmund (Carl Michael Lindner), create and enact increasingly imaginative rituals. Only the eldest child, James' daughter Shelly, refuses to participate due to her disgust at the dishonesty perpetrated by her father.
Taking advantage of her curiosity, James tricks Veronica into participating in his false documentary. When she discovers the truth, she is initially angry, but later helps James continue his fraud. Ruth Allen travels to New Guinea, discovering no tribe in the location specified by James. She transmits the news via fax to a colleague, who exposes James at a gala. James' imaginative son, Mickey, improvises a lie, that the Shelmikedmu hide by means of a magical ritual known only to them.
Unknown to the majority of the characters, Shelly has contacted the New Guineans befriended by her family during the futile search for the lost tribe, urging them to masquerade as the Shelmikedmu in order to disappoint Ruth Allen. The ruse succeeds, and the accusation of fraud is abandoned. James, relieved of his worries, ends his fraud. Because Veronica has become sexually involved with him during her participation in his deceit, she assumes the role of a mother toward the children, though she is not explicitly said to marry James.
- Richard Dreyfuss as Professor James Krippendorf
- Jenna Elfman as Professor Veronica Micelli
- Natasha Lyonne as Shelly Krippendorf
- Lily Tomlin as Professor Ruth Allen
- Barbara Williams as Professor Jennifer Harding Krippendorf
- Gregory Smith as Michael "Mickey" Krippendorf
- Carl Michael Lindner as Edmund Krippendorf
- Stephen Root as Gerald Adams
- Mila Kunis as Abbey Tournquist
- David Ogden Stiers as Henry Spivey
Krippendorf's Tribe opened at #7 in its opening weekend with $3,316,377. By the end of its domestic run, the film grossed a mere $7,571,115.
The film received generally negative reviews; review aggregate Rotten Tomatoes gives the film a 14% rating.