When the "Cheaper by the Dozen" movies were made, neither Steve Martin nor Bonnie Hunt, who played the parents of 12 children, had ever had a child in real life. Steve Martin first became a father years later in December 2012, when his wife Anne Stringfield gave birth to his first child, a daughter named Mary.

Real baby and childhood pictures of Hilary Duff and Alyson Stoner were used for the "photo albums" of their characters.

Carmen Electra is allergic to dogs. When the Bakers go to the Murtaughs' house, their dog Gunner jumps all over her. When the Bakers are leaving, tiny red dots are all over her body.

The Bakers cabin for the movie was built and then torn down after filming.

This film is a sequel to a remake of a film that was based on a book that was based on a true story. This means it is four steps away from its source material.

Steve Martin and Eugene Levy appeared in the Father of the Bride movies together.

Steve Martin and Eugene Levy both appeared in "Bringing Down the House" with Queen Latifah.

Events in the Labor Day Cup included: the Egg Toss, Wheelbarrow Race, Diving, Sack Race, Archery, Egg and Spoon Race, Water Treadmill, Volleyball, and the Tie-breaker Canoe Race. Not seen, but shown on the scoreboard were: Tug-O-War, Baseball Dunk, and Water Skiing.

Adam Shankman previously directed Morgan York in The Pacifier (2005)

Eugene Levy and Robbie Ammel who plays one of his kids have acted together in the movie American Pie: Beta House.

This is the second movie that Bonnie Hunt's character can be seen dancing on a dock with her on-screen husband. The first was in Beethoven the 2nd while they were also vacationing to a lake with the family and puppies.

The movie pays homage to Romeo and Juliet; with the Murtaughs and the Bakers spoofing the Montagues and the Capulets; with Eliot Murtaugh and Charlie Baker spoofing Romeo Montague and Anne Murtaugh and Sarah Baker spoofing Juliet Capulet.

The Kinsman twins, Brent and Shane both appeared on Desperate Housewives (2004) with Kathryn Joosten.

This was the first and only Cheaper by the Dozen movie to be Filmed in Panavision (anamorphic) 2.39:1.

Hilary Duff has an eating disorder during the movie.

Charlie's girlfriend Beth does not appear in this film.

Originally title was "Cheaper by the 2 Dozen"