- Ability over Appearance: Ofelia was written to be a younger girl, aged seven to nine. However del Toro was so impressed with Ivana Baquero (who was twelve), he rewrote Ofelia's age to accommodate her.
- Acting for Two: Doug Jones plays both the Faun and the Pale Man.
- Based on a Dream: Del Toro got the idea of the faun from childhood experiences with "lucid dreaming". He stated on The Charlie Rose Show that every midnight, he would wake up, and a faun would gradually step out from behind the grandfather's clock.
- Big Name Fan: Björk and Stephen King. The former was inspired to write the song 'Pneumonia' after seeing the film. The latter sat beside del Toro at a screening and squirmed during the Pale Man scene. Del Toro compared his reaction to that with winning an Oscar.
- Doing It for the Art: Guillermo del Toro gave up his director's salary to see this film realised.
- Doug Jones, who plays the Faun, does not speak Spanish. He learned all of his lines and Ofelia's in phonetic Spanish so he would know when to speak. Not only that, but he couldn't hear her either because the servos in the costume were so loud. So Jones had to perform all his scenes completely deaf and lip-read Ofelia's lines in a language he didn't speak. His voice was dubbed over in the final product, but the dub actor praised Jones' efforts for allowing him to flawlessly synch his readings with the Faun's mouth movements.
- Fatal Method Acting: Narrowly averted. Actor Manolo Solo was nearly killed when horses fell on top of him.
- Image Source: This film provides the page image for:
- Inspiration for the Work: Del Toro drew inspiration from Lewis Carroll's Alice books, Jorge Luis Borges' Ficciones, Arthur Machen's The Great God Pan and The White People, Lord Dunsany's The Blessing of Pan, Algernon Blackwood's Pan's Garden and Francisco Goya's works.
- Playing Against Type: Much of the cast. Sergi Lopez (Captain Vidal) typically played slimy, arrogant creeps who were somewhat Laughably Evil. Alex Angulo (Doctor Ferreiro) had been considered a lightweight comedic actor. Maribel Verdu (Mercedes) had played mostly love interests, and her most famous role (at least in the English-speaking world) had been Luisa Cortés in Y Tu Mamá También.
- Self-Adaptation: Del Toro wrote the novelization and is writing the stage musical.
- What Could Have Been:
- Del Toro was debating between doing this movie or directing ''The Chronicles of Narnia''. Coincidentally, Narnia also has a faun as an important character and a portal to another world. After he nearly lost the book's notes by leaving them behind in a taxi cab, he saw it as a sign to pursue his passion project.
- The first outline of the story was about an adult woman that found a hidden labyrinth behind an old house's bookcase. She would then be raped by a faun living inside the labyrinth, and as a result she would give birth to a magic-powered baby. Guillermo del Toro is that weird.
- An earlier draft of the script had the situation more ambiguous as to whether the magic was real or not (as Ofelia would encounter a dragon that speaks with Vidal's voice). In the finished film, the magic is definitely real, insofar that Del Toro even said it himself
- This plot idea incidentally bears some resemblance to Arthur Machen's The Great God Pan. The movie that happened ends up taking more influence from a different Machen story, The White People, which features a little girl associating with dangerous fairies.
- The Pale Man wasn't originally in the movie. The scene was originally meant to be Ofelia being tasked to retrieve a diamond from a sleeping dragon's hoard. The dragon would wake up when she removed a goblet from the hoard. It would then chase her, whilst speaking with Vidal's voice.
- Del Toro's Cabinet of Curiosities (an art book that collects some of the director's sketches, complete with English translations) shows that one of the earlier incarnations of the Pale Man was a wooden doll in a tree.
- The toad was originally going to be a more active adversary, leaping around in a large, womb-like cavern and attacking Ophelia. Unfortunately the animatronic model ended up not being up to the task even with the aid of CGI, so it was reduced to the lethargic beast in a narrow tunnel that we see in the film. Additionally del Toro realised that the toad wouldn't seem as scary in such a large set, so the tunnel was considered a better choice.
- Word of God:
- Some fans have interpreted the magic elements to be just Ofelia's imagination, and the ending to be a Dying Dream. Del Toro has claimed that he considers the magic real, but has left it open to interpretation.
- He's also claimed that Ofelia's famous Idiot Ball moment of eating food from the Pale Man's table to be a representation of her biggest virtue: courageous disobedience. According to him, it's a sign that she doesn't blindly follow orders - which emphasises her as a Foil to Vidal.
Trivia / Pan's Labyrinth