- Approval of God: Diana Wynne Jones was a fan of the film. Although she said that she originally envisioned Howl's castle as floating around, she liked Miyazaki's "legged" interpretation, and reprintings of the book made after the movie feature a legged version of the castle. It also seems to have inspired Mrs. Jones to write additional stories of Howl and Sophie, and while a third was published, she passed away while writing the fourth.
- Awesome, Dear Boy: Christian Bale said he'd play any role in the English dub after he saw Spirited Away and loved it. He didn't expect to land the title role.
- Celebrity Voice Actor:
- Creator's Favorite Episode: This is Hayao Miyazaki's favorite of his movies.
- Crossdressing Voices: The Witch of the Waste, but only in the Japanese version, where she was voiced by Akihiro Miwa, a Japanese actor and drag queen.
- Fake American: Christian Bale uses an American accent in the dub of the film. Ironically, Howl's eventually revealed backstory in the book reveals him to be a Welshman like Bale himself.
- Fake Brit: Jena Malone uses an English accent in the dub to play Lettie - to better match with Emily Mortimer and Jean Simmons voicing her sister. Funnily enough, she'd do the same in Pride & Prejudice (2005) around the same time.
- Pop Culture Urban Legends: A fan rumor is that Hayao Miyazaki was inspired to make the film after visiting the Strasbourg Christmas Market.
- Referenced by...: In Hellboy (2019), Baba Yaga's walking home resembles the titular castle, in contrast to the simple cabin she has in the Hellboy comics and the folklore.
- Spell My Name with an "S"
- Due to phonetic translation from English to Japanese and back, the character known as Michael in the books became "Markl" in the film. To make matters worse, whenever his name is spoken, it sounds more like "Marco" than anything else.
- The Swedish and Norwegian dub doesn't only have the same mistranslation, they also call Howl "Hauru", for the same reasons. Slightly justified in that they were trying to lip sync the movie, but it still comes off a bit awkward.
- Howl's called "Hauro" in the German dub and the mistranslation of Markl also took place.
- This is justified, as in Japanese (the original language of the film), Howl is written (and pronounced) "Hauru" (ハウル). Neither "Hauru" nor "Howl" have a meaning of their own in German, anyway, and the original book is all but unknown there. The German title just translates to "The Strolling Castle".
- The same thing happens with the name of Sophie's (step)mother. In the book her name was "Fanny". While she is never called by name in the movie, her name is written as "Honey" in the art book. The romaji for both words is different (Fanny = ファニー, Honey = ハニー), but the pronunciation is nearly identical ("Fanī" and "Hanī", respectively).
- Stunt Casting: Lauren Bacall was cast as the Witch of the Waste in the English dub partly because she was one of Hayao Miyazaki's favorite actresses.
- Throw It In: The distinctive growl that Christian Bale uses as Batman can be heard in the English version. This is because he was preparing for Batman Begins at the time.
- Two Voices, One Character: For the English release, Emily Mortimer played Sophie's younger self and the late Jean Simmons played her older self.
- What Could Have Been: Director Mamoru Hosoda was originally brought on to helm the project, but was taken off during the early stages of production.
Trivia / Howl's Moving Castle