My Best Friend's Girl follows Tank (Dane Cook), a self-proclaimed rebound specialist who is hired by recently dumped men to help get their ex-girlfriends back. The masterful Tank takes these women out on a date that guarantees it will be the worst, most offensive experience they've ever had -- and they promptly run back to their old boyfriends with newfound appreciation.
Then Tank gets hired by his devastated roommate and best friend Dustin (Jason Biggs) to help him win back Alexis (Kate Hudson). Dustin and Alexis had been dating -- chastely -- for only five weeks when Dustin pours his feelings out to her over dinner. Stunned, Alexis breaks up with Dustin instead because she feels that she needs to play the field. Alexis has only had longterm serious relationships so far so she wants to experiment with commitment-free casual dating (and sex) for awhile.
Desperate, Dustin turns to Tank for help in getting her back. Tank reluctantly agrees, but discovers that Alexis is immune to his charms (or lack thereof) and she actually enjoys their awful date. They soon have a sex buddy relationship, even as an oblivious Dustin tries to win Alexis back. Much to his surprise, commitment phobic Tank finds himself falling for his best friend's girl. What will happen when the truth comes out?
