Tom Baker is a football coach at a small rural college in Midland, Indiana, where he raised twelve children, and his wife, Kate, has written her story into a book and hopes to send it to her friend to publish the book. Tom unexpectedly receives an offer from his old friend and football teammate Shake McGuire to coach at his alma mater in his hometown of Evanston, Illinois. Tom accepts the offer, and he and Kate begin making plans on moving to Evanston. The kids find out and demand the move be put to a vote, even though Tom says it won't have any power. He loses the vote, even after he and Kate join, but goes ahead with the move anyway, claiming there will be more money and that they will be a "happier and stronger family". The atmosphere at the Bakers' new house is tense and the situation at school is even worse.
When her book is ready to pick up for publication, Kate is required to do a national book tour to promote it. Tom thinks that he can handle everything in the family's household while Kate is away, so he decides to hire the family's oldest child, Nora, and her self-absorbed boyfriend, Hank, to manage the children. When Nora and Hank arrive, the children plan to make Hank the target of their prank by soaking his underwear in meat and assisting the Bakers' pet dog, Gunner, to attack him by chewing his bottom, prompting him to refuse to assist in babysitting. As a result, Nora drives off with Hank, while Tom lectures them for their prank. After Kate departs for her book tour, Tom realizes that he cannot handle the children on his own after a chaotic night. In reply to this revelation, Tom tries to hire a housekeeper, but nobody is willing to work with a family as large as the Bakers, so Tom decides to bring the football players from work into the family's house for game practicing in the living room to prepare for the Saturday night football game as the children perform chores and their household games. However, the children start causing trouble at school. Kate overhears from the children about the chaos and cancels the book tour to take charge of the situation. Kate's publisher decides to create an additional promotion for her book by inviting Oprah Winfrey to tape a segment about the Bakers in their home instead.
Despite much coaching from Kate, the Bakers are not able to demonstrate the loving, strongly bonded family that Kate described in her book. When Mark becomes upset that his pet frog has died, a heated fight erupts moments before the segment starts, leading the cameramen to call Winfrey to cancel it. Mark runs away from home, prompting the Bakers to find him. Tom indulges a hunch that Mark is trying to run back to the Bakers' old home, and eventually finds Mark on an Amtrak train departing from Evanston, Illinois to Midland. Reuniting with the rest of their family, the Bakers begin to address their issues with each other, and Tom ultimately resigns from his position at his alma mater with Shake.Steve Martin as Tom Baker, the father
Bonnie Hunt as Kate Baker, the mother
Piper Perabo as Nora Baker, 22
Tom Welling as Charlie Baker, 17
Hilary Duff as Lorraine Baker, 16
Kevin Schmidt as Henry Baker, 12
Alyson Stoner as Sarah Baker, 11
Jacob Smith as Jake Baker, 10
Forrest Landis as Mark Baker, 9
Liliana Mumy and Morgan York as Jessica and Kim Baker, 7 fraternal twins
Blake Woodruff as Mike Baker, 6
Brent and Shane Kinsman as Kyle and Nigel Baker, 5 identical twins
Steven Anthony Lawrence as Dylan Shenk
Paula Marshall and Alan Ruck as Tina and Bill Shenk
Richard Jenkins as Shake McGuire
Ashton Kutcher as Hank
Tiffany Dupont as Beth
Cody Linley as Quinn
Jared Padalecki as an unnamed bully
Joel McCrary as Gil
Dax Shepard as Camera Crew Member
Regis Philbin as himself
Kelly Ripa as herself
Frank Welker as Gunner (voice)
Wayne Knight as Electrician (uncredited)
The film's Director Shawn Levy makes a cameo as a reporter
The film was mostly shot in various cities in Los Angeles County with the exception of the outdoor scenes of the Baker Family Home in Midland, Indiana which was shot outside of Petaluma and the Midland Train Station scene which was filmed in Santa Rosa, California.
A sequel, Cheaper by the Dozen 2, was released in the United States on December 21, 2005.
Other compositions used in the movie are "Classical Gas" by Mason Williams and Carl Orff's "O Fortuna", among others.
The review aggregation website Rotten Tomatoes reported a 24% approval rating based on reviews from 118 critics, with an average score of 4.5 out of 10, and the site's consensus reading: "In this family of twelve children, much chaos ensues, but little hilarity." On Metacritic, which determines a normalized rating from mainstream critics, the film received a score of 46 out of 100 based on 30 reviews, indicating "mixed or average reviews." Despite initial reactions, the film was given "Two Thumbs Up" from Roger Ebert and Richard Roeper on their television show, and became a box office hit. The film opened at #2 ranking in US$27,557,647 in its first opening weekend and, despite being kept from the top spot by The Lord of the Rings: The Return of the King, went on to gross $190,212,113 worldwide. Ashton Kutcher was nominated for a Golden Raspberry Award for Worst Actor for his performance in this, and two other films.
The film was released on VHS and DVD on April 6, 2004.