Catweazle is a British children's fantasy television series, starring Geoffrey Bayldon in the title role, and created by Richard Carpenter for London Weekend Television. The first series, produced and directed in 1969 by Quentin Lawrence, was screened in the UK on ITV in 1970. The second series, produced and directed in 1970 by David Reid and David Lane, was shown in 1971. Both series had thirteen episodes, most written by Carpenter, who also published a book for each series based on the scripts.

A former actor, Richard Carpenter had decided to switch to screenwriting in the 1960s. While driving home from his brother-in-law's farm, Carpenter became lost in the countryside. While consulting a map, Carpenter noticed the name "Catweazle" scratched into an old stone gatepost. The name stuck with Carpenter and he decided to use it. Carpenter was inspired to create a TV show about a wizard after seeing a picture of a "wizardly old man" in the bottom left corner of the Hieronymus Bosch painting "Christ Crowned with Thorns". Carpenter then decided that his wizard character would be a time traveller, and would travel from the Middle Ages into the twentieth century. Carpenter was also interested in the writings of historian Margaret Murray and occultist Gerald Gardner, and incorporated some of their ideas about witchcraft into the scripts.

The premise in the first episode is that an 11th-century bumbling wizard named Catweazle (Geoffrey Bayldon) is pursued by soldiers through a wood, carrying only his magic charm and his toad familiar. He says a spell as he jumps into a pond. When he emerges from the pond he believes that he has flown from the woods; in fact he has jumped 900 years into the future.

Catweazle arrives on a farm in rural England in the year 1969 and befriends a farmer's son, a ginger teenager named Edward Bennet, nicknamed Carrot (Robin Davies), who spends most of the rest of the series attempting to hide Catweazle from his father (Bud Tingwell) and the farmhand Sam (Neil McCarthy). Catweazle searches for a way to return to his own time while hiding in a disused water tower on abandoned Ministry of Defence land, which he calls Castle Saburac, with the toad called Touchwood (as touching wood is believed to bring good fortune). Whenever he is spotted, he uses his magic amulet to hypnotize people into forgetting that they saw him.

The second series featured a 12-part riddle that Catweazle, now in 1970, attempts to solve at the rate of one clue per episode, the solution (as he thinks) being revealed in the 13th.

A third series, which was apparently to be set on the Bennets' farm from the first series rather than the stately home of the second series, never got past the drafting stage.

Catweazle mistakes all modern technology for powerful magic (an example of Arthur C. Clarke's third law that "Any sufficiently advanced technology is indistinguishable from magic"), particularly "elec-trickery" (electricity) and the "telling bone" (telephone). Often he tried spells that failed and he would sigh, "Nothing works". Feeling flushed with success in the final episode, his last words were "Everything works, Touchwood! Everything works!".

Both series were shot on 16mm film. The first series was mostly shot on location at Home Farm, Ripley Road, East Clandon, (near Guildford) in Surrey, England in 1969. The second was mostly filmed around the Bayford/Brickendon area of Hertfordshire in 1970 (S02E12 shows scenes of Brickendon and near Bayford station). Interior scenes were filmed at [the now defunct] Halliford Studios, Manygate Lane, near Shepperton.