Caillou is a children's television show based on the books by Christine L'Heureux and illustrator Hélène Desputeaux. Many of the stories in the animated version began with a grandmother (who is also the show's narrator) introducing the story to her grandchildren, then reading the story out of the book. Caillou first aired on Canada's Teletoon channel in 1998; it later made its US debut on PBS on September 4, 2000 and aired its series finale on October 3, 2010. The action of the Caillou story takes place in Canada, though that is never explicitly referenced in the dialogue. Caillou television show also began airing on Treehouse TV on September 7, 2009.

Caillou is a 4-year-old boy who delights in the small wonders of the world around him, embellishing everything he sees with his rich imagination. Surrounded by his parents, his little sister, Rosie, his grandparents and friends his age, Caillou discovers the world and just can't wait to grow up! Everything around Caillou is an excuse to embark on exciting adventures, learn new things and have fun. Whether he's at school, at home or in a park, Caillou finds opportunities for learning and growing everywhere!

Caillou is a wide-eyed four-year-old who learns about life - one adventure at a time! From his own backyard to his very first airplane ride, Caillou discovers the wonder and excitement of being a little boy in a very big world.

Each episode of Caillou television series is a slice of Caillou's life. Thanks to his vivid imagination, ordinary, everyday events quickly become exciting adventures where Caillou can play "make-believe". But Caillou can tell the difference between real life and pretending. When he is done playing make-believe, Caillou happily returns to the familiar daily routine of a 4-year-old. Indeed, each Caillou episode begins and ends firmly anchored in the real world.

Designed for preschoolers, the Caillou television series is composed of 30 minute episodes divided into three 7 minute adventures. In each adventure, Caillou discovers the big, wide world, experiences new things, shares his imaginary adventures with us and sometimes, even sings for his little viewers!