- Awesome, Dear Boy: Joan Fontaine was a co-producer and lobbied to play the role of Gwen Mayfield because she was a huge fan of the book the film was based on.
- Creator Backlash: Screenwriter Nigel Kneale expressed dissatisfaction with the finished film, due to the Genre Shift his script suffered.
- Dawson Casting: Ingrid Boulting was nineteen when she played the fourteen-year-old Linda Rigg. Likewise Martin Stephens was seventeen playing a boy at least two years younger. This is especially noticeable whenever they're in class; they look significantly older than their classmates.
- Executive Meddling: The original script poked fun at the idea of a coven of witches in rural England. The production team wanted the film to be completely serious, and removed most of the dark satire.
- Fake Brit:
- Mrs Dowsett is played by Irish actress Carmel McSharry.
- Linda Rigg likewise is played by South African model/actress Ingrid Boulting.
- Follow the Leader:
- British films based around black magic started popping up right after this one - notably The Devil Rides Out, Eye of the Devil and of course The Wicker Man (1973). Rosemary's Baby came out in America just one year later too.
- The film itself was also following the trend in the 60s of Hollywood's middle-aged leading ladies headlining horror films and thrillers - What Ever Happened to Baby Jane?, Strait Jacket, Hush...Hush, Sweet Charlotte, Lady In A Cage.
- Hey, It's That Place!: Heddaby also appears in Chitty Chitty Bang Bang.
- Market-Based Title: It was released as The Devil's Own in the US, which was the title of the book it was adapted from.
- Name's the Same: No relation to Roald Dahl's novel The Witches.
- Playing Against Type: Martin Stephens in the 50s and 60s had made a name playing various Creepy Children. Here he's one of the few non-creepy people in Heddaby.
- Ripped from the Headlines: The book was first written after a real life murder of an old man in a rural community - supposedly so his blood would enrich the soil. The same case inspired Eye of the Devil and The Wicker Man (1973).
- Star-Derailing Role:
- Joan Fontaine's career had diminished in the 60s - getting typecast as socialites - and her previous role before this had been a supporting one in Tender is the Night. This film was not a Box Office success and after a couple of TV appearances, Joan retired from acting.
- It also marked the final performance of Martin Stephens, and he retired from films not long after.
Trivia / The Witches (1966)