Director Curtis Hanson approached Toni Collette before filming and asked the actress about gaining weight for the part. Collette had complied and proceeded to gain twenty-five pounds for the part, which she subsequently lost during the film's shooting, which is to reflect her character.
In the book, the dog Maggie steals was originally a purebred pug. But Curtis Hanson opted to change it, as he cited that movies tend to inspire people to adopt the same dog breed featured in a film. Hanson opted for a mixed breed, hoping that it would inspire people to adopt a shelter pet instead.
In the scene where Maggie is auditioning for MTV, the teleprompter says they are going to premiere a new Eminem music video. This is a nod to director Curtis Hanson's previous film, 8 Mile (2002), starring and inspired by the life of the rapper.
According to director Curtis Hanson, during the time Honeybun, the mixed breed dog Maggie steals from the groomer, had the crew become quite taken with her. When her scenes were wrapped, Hanson said crew members had approached him about possibly adopting the dog. Hanson opted to have Honeybun's trainer adopt her, as he felt the dog had a rapport with the trainer.
The episode Ella and her friends are watching of Sex and the City (1998-2004) is "Valley of the Twenty-Something Guys." Interesting to note, three actors in In Her Shoes (2005) appear in other "Sex and the City" episodes: Mark Feuerstein in "They Shoot Single People, Don't They?," Francine Beers in "The Good Fight," and Marcia Jean Kurtz in "Oh Come All Ye Faithful."