The third season of Wizards of Waverly Place aired on Disney Channel from October 9, 2009 to October 15, 2010. The Russo children, Alex, Justin, and Max Russo continue to compete to become the leading wizard in their family and meet many friends and adversaries along the way. Maria Canals Barrera and David DeLuise co-star as their parents and Jennifer Stone co-stars as Alex's best friend, Harper Finkle. This is the first season of the series to be broadcast in high-definition.
Justin becomes fed up with Alex constantly going through his stuff and creates a female monster to guard his room and to think like Alex. However Justin's plan backfires when the monster and Alex become fast friends.
The Russo family comes together to create the scariest haunted house ever for Halloween.
When Justin completes his ten-thousandth spell, he signs up for a Monster Hunting class.
Justin is taking his Monster Hunting Course and finds out that Juliet and her vampire family are the monsters he has been looking for!
Justin is summoned to track down a scary mummy as part of his monster hunting duties. He and Juliet set off to the museum to track the monster, but things take a turn for the worse when Justin and Juliet become trapped in the museum. Meanwhile, Alex tries to separate Max from his conscience after he starts excelling in his wizard studies.
When Harper learns that her family is moving away, the Russos offer to let Harper live with them. While Alex and Harper clean out the basement to make room for Harper's stuff, Alex shrinks herself down to fit in her old doll house, but Jerry and Theresa give the doll house away to a little girl named Olive with Alex still in it.
After Alex uses magic to help Harper win a marathon, she recreates the activities for her friend, so a very upset Harper can win on her own. Meanwhile, Justin decides to enter the marathon to win the first athletic trophy for the Russo family.
Alex starts to date Mason, a transfer student from England. He is perfect in very way with the exception of his view of art. In order to make him a better artist, Alex takes matters into her own hands by putting a spell on him.
Justin and Max continue to search for Juliet. Meanwhile, Mason and Alex continue dating but Mason keeps running away from Alex before the evening. She becomes suspicious and follows him one night. Alex and Harper discover that Mason is actually a werewolf.
Alex has a crush on a boy who won't talk to her because of her sour attitude. She then uses magic to make herself positive. Justin joins the basketball team and tries to capture a big senior year moment on video
Justin’s chances at becoming Student Body President are put in jeopardy after someone wallpapers Principal Laritate’s office with posters from Justin’s campaign and he is accused of masterminding the prank. Meanwhile, Alex befriends Stevie, a rebellious new girl in school, and Jerry, Max and Harper get stuck on a Ferris wheel during their trip to Coney Island.
Alex, Justin and Max are shocked to discover that international music sensation Shakira is actually their Uncle Kelbo, who has been abusing one of the Main Eleven Wizards Rules.
After Harper's lunchtime Shakespeare impressions are a total bust, Alex and Stevie ask Justin to hire a rock band to play at lunchtime. Justin agrees, feeling that he owes Stevie since she got him elected to become Student Body President.
Harper is desperately trying to remember something, but she cannot. Alex offers to help Harper recall her memory, so she casts a spell on her. Harper then remembers: Stevie is a wizard, and she saw her cast a spell. Alex and Harper confront Stevie, and she confirms their suspisions by casting a spell in the ground that opens up a warp hole and a student falls in. Alex is happy that she has a wizard friend, but Harper feels left out.
Alex discovers her friend Stevie is leading a wizard revolution. To the dismay of Justin and Harper, she decides to help Stevie with her quest to make sure no wizard ever has to give up their powers again.
When the school's superintendant fires Mr. Laritate because of Alex, Mr. Laritate gets a job at a western place. When the school hires a strict new principal, Alex transports Mr. Laritate back to the Old West in an attempt to show him that it's not what he thought it was and make him want to come back to Tribeca Prep.
Alex sells shirts she makes herself, but Justin makes her give the money to Student Council since she sold them on school grounds without permission. Then when she wins a citizenship award, some feel she does not deserve it.
After Jerry is bitten by a bug from the wizard world he is transformed into a giant bug himself. Meanwhile, Harper joins the Alien Language League Zeke and Justin are in and they hold the annual banquet at the Sub Station.
Harper and Alex find out that Max has a girlfriend named Nancy Lueke, but has been keeping it a secret so not to get embarrassed by his family. Later his mother finds out about it and tells him that it's not okay to hide the truth from anyone. Since he took his mothers advice, he tells Nancy his secret about being a wizard. The Russos make up another lie to cover the truth, and Nancy breaks up with him.
Alex sets up Harper on a date with Justin's best friend Zeke, but the relationship doesn't go as she planned. Meanwhile, Justin prepares a project for a science fair.
Alex reveals she has made a clone of Justin and he has been attending college for the past four years. But, when she tries to undo the spell the two Justins to merge into one.
Justin and Alex are chosen create an issue of the Captain Jim Bob Sherwood comic book, with Justin writing the story and Alex doing the illustrations. But when they can't agree on their ideas, Alex uses magic and displaces Captain Jim Bob from the comic book, leaving him loose out in the city.
Harper and Alex join Harper's parents in a signing act. But Alex finds out it is a lot of working and wants to go home.
Alex is punished for buying a vending machine with her parents money. Alex sees a mirror that says "Do Not Go In Alex". After Alex steps through a magical mirror, the universe becomes all about her, and when the mirror breaks after she doesn't want to come back to the real world, Alex is possibly stuck in the parallel 'you-niverse' forever.
Wilmer Valderrama guest stars on Wizards of Waverly Place in the episode 'Uncle Ernesto'. Uncle Ernesto has no idea that the Russo's have magic abilities, so they promise a magic free night so that he can come over for a birthday dinner. Meanwhile, the kids get a magical chicken that can tell them the answer to anything. They ask it the age-old question, "Which one of us is going to win the wizard competition?" But when the chicken runs amuck, they have to catch it before he lays the answer and Uncle Ernesto finds out about magic.
When Alex and Harper witness a forlorn Justin moping around the Sub Station due to his depression over losing Juliet, they devise a plan to help him move on, in which Alex magically transforms Harper into Juliet.
While watching a news broadcast, Alex discovers that Mason (in wolf form) is in the Poconos Mountains trapped by country wizards. The country wizards will only give back Mason if Alex trades them their portal. Alex then discovers that the country wizards have turned Mason into a half wolf form. But can she live to be with Mason like this without being embarrassed by him?