Code Lyoko (French pronunciation: [kɔd ljɔko]; Stylized as CODE: LYOKO in Season 1 and in all caps starting in Seasons 2 to 4) is a French animated series created by Thomas Romain and Tania Palumbo and produced by Antefilms Production (season 1) and MoonScoop Group (seasons 2–4) for France 3 and Canal J, with the participation of Conseil Général de la Charente, Pôle Image Magelis, Région Poitou-Charentes and Wallimage. The series centers on a group of teenagers who travel to the virtual world of Lyoko to battle against a malignant artificial intelligence known as XANA who threatens Earth with powers to access the real world and cause trouble. The scenes in the real world employ traditional animation with hand-painted backgrounds, while the scenes in Lyoko are presented in 3D CGI animation. The series began its first, 97-episode run on September 3, 2003, on France's France 3, and ended on November 10, 2007 and on Cartoon Network in the United States on April 19, 2004.

A follow-up series, Code Lyoko: Evolution, began airing at the end of 2012. This "sequel" to the series featured live-action sequences for scenes taking place in the real world instead of its traditional 2D animation but retained the iconic CGI for scenes taking place in Lyoko, now with an updated artstyle. Unlike the original, it was never dubbed into English (With the exception of the show's trailer and episode 5 on Kabillion). The show consisted of 26 episodes with the final episode airing in late 2013, leaving off on a cliffhanger with no second season or other sequel series planned as MoonScoop later filed for bankruptcy in 2014.