Caillou ( kah-yuu, -⁠yoo; French: [kaju], stylized in lowercase) is an animated educational children's television series that aired on Teletoon (both English and French versions) – with the first episode airing on the former channel on September 15, 1997 – until the fourth season. After that, the fifth season channel was moved to Treehouse TV, and the series finale aired on April 17, 2011. It also aired on PBS and the PBS Kids Channel.

Based on the books by Hélène Desputeaux, it focuses on a four-year-old boy named Caillou who is fascinated by the world around him. The series was produced in Canada by the CINAR Corporation (later Cookie Jar Entertainment), while the fifth and final season was produced in association with the South African studio Clockwork Zoo.

In 2023, it was announced that the show would be rebooted. It was originally set to premiere on Peacock with 52 eleven-minute episodes some time in 2023, but ultimately began streaming on February 15, 2024, with a batch of seven episodes.