Audio problem: In the scene after Reese Witherspoon and Luke Wilson are returning from questioning the ex-wife of the murder victim at a spa, they are driving up in Luke's car. You can clearly see, as they get closer to the camera, that what you hear Luke saying isn't what his lips are saying. It was a very obvious dub over...and a very bad one.
Continuity mistake: In one of the courtroom scenes, you can see Paulette (the nail technician) enter with the UPS guy who has plaster on his nose - the plaster is white and has two brown pieces of tape over it. At the end of the same scene when everyone is exiting the courtroom, the UPS guy has no plaster only two, now white, pieces of tape on his nose.
Continuity mistake: When Elle is called to the lawyer (Callahan), she holds some files and no bag. After he tries to pick her up, she leaves with empty hands. A few seconds later, in the corridor, she's walking with her bag on her shoulder. Where could she get it from? And did she have the time to put the files in? (01:12:10)
Continuity mistake: Near the end of the movie, when Elle walks out with Brooke, she is holding Bruiser in her left folded arm, with her dog-carrier purse, that looks like it has something in it, on her right shoulder. A few seconds later, when Warner approaches her on the steps, she has no dog but the purse looks empty.
Continuity mistake: When Reese Witherspoon is eating chocolates after being dumped, look closely at the box. When she finds one that she likes, there are two white ones one row in from the back. Two seconds later, just before she throws the box at the screen, there's only one white one, and it's moved forwards a row. (00:11:00)
Plot hole: In the courtroom scenes, the victim's daughter, Chutney, is examined by the prosecution. This would mean that she has been sworn in. Yet, when she is examined by the defense, she is sworn in again. Wouldn't she still be considered "under oath"?
Factual error: We know that Elle and Warner are both in Callahan's class together, but that Warner is not in Stromwell's class with Elle. However, Harvard, like most law schools, divides its first year class into sections that take every class together. Warner should either be in all of the same classes as Elle or none of them.
Other mistake: Legally Blonde was shot at a Delta Zeta Sorority house (a Z is very easy to change into an N). Proof of this can be seen in the scene at the beginning of the movie when there is a shot of the entranceway floor. On the emblem of the floor there is a Greek delta and what at first glance appears to be a N. However, if you look at the delta at the proper angle the N is a Z.