Caillou ( kah-yuu, -⁠yoo; French: [kaju], stylized in lowercase) is an educational children's television series which 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, it moved to Treehouse TV for season five. The series finale aired on October 3, 2010. 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.The show is being followed by a computer-animated reboot series. It was originally set to premiere on Peacock with 52 11-minute episodes some time in 2023, but for unknown reasons, it was never released. However, it was confirmed to start streaming on February 15, 2024.