Blue Peter is a British children's television entertainment programme created by John Hunter Blair. It is the longest-running children's TV show in the world, having been broadcast since October 1958. It was broadcast primarily from BBC Television Centre in London until September 2011, when the programme moved to dock10 studios at MediaCityUK in Salford, Greater Manchester. It is currently aired on the CBBC television channel on Fridays at 5 p.m. The show is also repeated on Saturdays on BBC Two, Sundays at 9:00 a.m. and a BSL version is shown on Tuesdays at 2:00 p.m. For decades the show was regularly broadcast live; however, in March 2025, a fully pre-recorded format was introduced.

Following its original creation, the programme was developed by a BBC team led by Biddy Baxter; she became the programme editor in 1965, relinquishing the role in 1988. Throughout the show's history there have been forty-three official presenters; currently, it is hosted by Joel Mawhinney, Abby Cook and Shini Muthukrishnan.

The show uses a nautical title and theme. Its content, which follows a magazine/entertainment format, features viewer and presenter challenges, competitions, celebrity interviews, popular culture, and sections on making arts and crafts items from household items. The show has had a garden in both London and Salford, known as the Blue Peter Garden, which is used during the summer and for outdoor activities. The programme has featured a number of pets including dogs, tortoises, cats and parrots. The longevity of Blue Peter has established it as a significant part of British culture and British heritage.