St. Joel's Catholic High School is the (fictional) high school in Northern Ontario that Scott Pilgrim attended from the age of 16 until he moved to Toronto. St. Joel's has a rivalry with nearby Benvie Tech High School.
On his first day at St. Joel's (he transferred in), Scott got in a fight ("an awesome fight" -which he lost) with a bunch of bullies within less than fifteen minutes after joining the school. Outside the principal's office he befriended fellow new kid Lisa Miller. Later in geography class he met Kim Pine after being assigned as her partner on a presentation. The three kids formed the band Sonic & Knuckles to play St. Joel's "Lunchapalooza 9" (along with Quentin, Imperial Otter, Sarah Walker, and Nemesis). At one point, a gang of boys from Benvie Tech, led by Simon Lee, attacked St. Joel's, beat up all the male students, and kidnapped Kim. When Scott (who had missed the bus earlier that day) learned of this, he went off to Benvie Tech, defeated Simon Lee, and rescued Kim. However, this whole incident is later revealed to be a false memory planted in Scott's head by Gideon Graves.
St Joel's is most likely based on O'Malley's real high school, St. Thomas Aquinas Catholic Secondary School, in London, Ontario.