Caillou is a Canadian animated educational children's television series that was first shown on Teletoon, with its first episode airing on the former channel on September 15, 1997; - and was later shown on Treehouse TV, with its final episode being shown on that channel on October 3, 2010. The series aired in the US on PBS in 2000. The series is based on the books by author Christine L'Heureux and illustrator Hélène Desputeaux. It centers on a 4-year-old boy named Caillou who is fascinated by the world around him. PBS stopped airing Caillou on January 1, 2021, but returned to US airwaves on the Cartoonito block on Cartoon Network on September 13, of the same year and the show is still viewable the official YouTube channel. Canada. Caillou's New Adventures, a continuation series is also still receiving new episodes on YouTube.
From sometime in 2007 until the week of 27 February 2012, Cartoonito UK aired a British dub of Caillou. Unfortunately, no clips of Caillou airing on the British version of Cartoonito can be found anywhere on the Internet. This show does aired on Tiny Pop, and it is also available on British streaming services such as Amazon Instant Video, Netflix and Tiddlers TV, It Also Used To Air On LivingTV's Former Tiny Living Block and Channel 4, but they use the Canadian dub. As of 2016, no Caillou VHSes or DVDs have been released in the UK, so that makes the British dub harder to find, however, Little Toons (a British shopping website) has some German Caillou DVD's with English audio tracks on them, but JaredCaptainAmerica43 saw a video of two Caillou episodes in English with German text (excluding the credits) and noticed it having the original dub, which means those DVD's don't have the UK dub. Also, Cartoonito would usually only air the show during the Early Morning hours (between 4:00 A.M. and 7:00 A.M.), meaning that it is even less likely that people who taped Cartoonito would even have footage of this dub, briefly before the show got removed, it's time slot at 6:50 A.M., was replaced by Cartoonito Karaoke, and when the show was removed from the lineup completely, it was replaced by Fireman Sam.
According to YouTubeFan43, in the British theme song, Caillou's mum's voice is redubbed while Caillou's singing voice from the original Canadian-English dub is used instead of being redubbed. The same happened in the UK theme songs of Shimmer & Shine, Arthur, Franklin, Puppy Dog Pals, Wildernuts, Miss Spider's Sunny Patch Friends, PAW Patrol, Wow Wow Wubbzy and some foreign dubs of The Adventures of Jimmy Neutron Boy Genius and The Fairly Oddparents. Also, according to Gilby1385, Caillou had a lower-pitched voice than the Canadian dub in the UK dub.
- The Cartoonito page for Caillou has been found. It does have some video clips, but they don't play (not even in Britain.). http://web.archive.org/web/20110923143538/http://www.cartoonito.co.uk/tv-show/caillou
- An older Cartoonito page for Caillou has been found, and the videos on that page don't require flash, but they require Windows Media Player. The videos on that page don't work on anyone's computer so far, but it is possible that they might work on someone else's. http://web.archive.org/web/20100326082802/http://www.cartoonito.co.uk/shows/caillou#REDIRECT
- Another Cartoonito page has been found which says has Caillou games, and might have videos of the UK dub on it. As of right now, nobody can seem to be able to access the page currently. Even attempts of using the Wayback Machine are unsuccessful with it only going back to 2016, likely when the game had likely already been discontinued. http://www.cartoonito.co.uk/tv-show/caillou/games_1
- In June 2020, A user by the name of HarryCallou has found a clip of British Caillou crying at 25 seconds in the video 
- In February 2021, A user called UmizoomiFan81 has found a 2 second clip, https://youtu.be/1N8qTkfBb_k https://youtu.be/WZx7MODuyas