Lyoko Warriors
- Jeremie Belpois
- Yumi Ishiyama
- Ulrich Stern
- Odd Della Robbia
- Aelita Schaeffer
- William Dunbar (Joined cast in Season 2, became a Lyoko Warrior in the end of Season 3)
Kadic Academy Students (Minor Characters)
Note: All students move up a grade in Season 3, and again in Evolution.
5th Graders
- Hiroki Ishiyama (Yumi's younger brother)
- Johnny Cleary (Hiroki's best friend)
6th Graders
- Anne-Sophie Munier
- Anouche Bedoyan
- Julie Vigourox
- Milly Solovieff (Kadic's reporter)
- Ninon Costes
- Sandra Dialo
- Tamiya Diop (Kadic's reporter)
- Veronique Fayolle
7th Graders
Other 8th Graders (besides Jeremie, Ulrich, Odd, and Aelita)
- Aelita Clone
- Alexandre Peppin
- Azra Ürgüp
- Bastien Roux
- Brynja Heringsdötir
- Claire Girard
- Elisabeth Delmas
- Heidi Klinger
- Herb Pichon
- Jean-Baptiste Pujol
- Jeanne Le Bihan
- Jeremie Clone
- Julien Xao
- Kelly
- Laura Gauthier
- Magali de Vasseur
- Matthieu Ducrocq
- Naomi N'guyen
- Nicolas Poliakoff
- Patrick Belpois
- Paul Gaillard
- Romain Le Goff
- Samantha Suares
- Sophie Florenceau
- Sorya Abulabbas
- Taelia
- Tania Grandjean
- Theo Gauthier
- Thiery Suarez
- Thomas Jolivet
- Valerie
- Yannick Piranet
9th Graders (besides Yumi and William)
- Anais Fiquet
- Caroline Savorani
- Christophe M'Bala
- Emily LeDuc
- Emmanuel Maillard
- Maitena Lecuyer
- Mathias Burrel
- Priscilla Blaise
- William Clone
Adults
Teachers and Staff of Kadic
- Gilles Fumet - Social Studies Teacher
- Gustave Chardin - Art Teacher
- Hans Klotz - School Psychologist
- Jean Pierre Delmas - Principal
- Jim Morales - Physical Education Teacher/Dorm Manager
- Mrs. Meyer - Math Teacher
- Nicole Weber - Office Secretary
- Rosa Petitjean - Lunch Lady
- Suzanne Hertz - Science Teacher
- Yolanda Perraudin - School Nurse
- Ms. Kensington - English Teacher
- Michael Rouiler
Villains
More Major Characters And More Minor Characters
- Kiwi
- Waldo Franz Schaeffer/Franz Hopper (Aelita's father)
- Anthea Hopper-Schaeffer (Aelita's mother)
- Takeho Ishiyama (Yumi's father)
- Akiko Ishiyama (Yumi's mother)
- Mr. and Mrs. Stern (Ulrich's parents)
- Michael Belpois (Jeremie's father)
- James Dunbar (William's father)
- Mr. and Mrs. Della Robbia (Odd's parents)
- Samantha Knight
- X.A.N.A. Aelita
- X.A.N.A. Yumi
- X.A.N.A. Odd
- X.A.N.A. Ulrich
- X.A.N.A. Franz Hopper
- Mister Pück (Aelita's childhood toy)
- Subdigitals