Teen Witch is about a teenager named Louise Miller. Louise has a lot of problems fitting in at school and is perceived by most of her other classmates as a nerd. Louise is sweet, but she is lonely because she has a hard time making friends. One afternoon, Louise is riding her bike when she gets into an accident. She wants to use the phone to ask for help, but the closest house is the creepy home that all of the kids swear is haunted. Louise musters up the courage to go to the house, where she meets Madame Serena, a strange old woman that is delighted to see Louise. Louise learns that she used to be a witch and was reincarnated as an ordinary teen. Serena informs her that on her 16th birthday, all of her old powers will return.
Sure enough, on the morning of her 16th birthday, Louise has magical powers that she did not have before. Immediately, she casts a spell to become more popular and to get the cute boy she has had her eye on for some time. She also uses her popularity to get revenge on a teacher that had been taunting her as well as some cheerleaders that had treated her poorly for so many years.
Ultimately, Louise goes a bit too far casting spells and turns everyone's world upside down. She realizes that it may be best if she does not use her powers at all and to try and make the best of her life on her own.
The lesson Louise learns is the key to the film. Teen Witch shows that being yourself is the most effective way to lead a happy life, and that it does not take magic spells to gain friends. Even though Louise is just using her past instincts as a witch, she has become a different person and wants to succeed in life on her own merits.