Because of the film's low budget, the girls' clothes are mostly from their own wardrobe. Catherine Hardwicke noted that as filming progressed, the girls began to dress similarly without being told to.
Catherine Hardwicke said she was only paid $3 to direct the film because no studio at the time wanted to make an R-rated movie about teen girls. She said, "every studio and every financier said, 'No, we can't make it. How could we make a movie that's gonna be R-rated with an unknown 13-year-old girl in the lead?' Everybody said no." So Hardwicke ultimately produced it herself with a budget of about $2 million, which she raised through independent equity financing, and only paid herself $3 so the rest could be used for film production.
During the belly piercing scene, Tracy says "What the fuck did you do". That was not scripted because Nikki Reed had actually poked the top of Evan Rachel Wood's belly with the needle. Reed was attempting to put pressure on her thumb so that the scene looked more realistic but her thumb slipped. Evan still has the scar to prove it.
During a live Q&A on Ustream to celebrate the film's 10th anniversary, hosted by Reed and Wood, the actresses claimed that neither of them can watch the movie since they both have such strong emotional reactions to the film.