In the DVD commentary, del Toro talks about his original story that goes something like this: pregnant woman goes to the mansion her husband works at to fix it up, woman falls in love with a faun in a labyrinth, faun asks her to give up her child to enter the magical kingdom, she does it. And you thought the final version was morbid. (Source)

Pan's Labyrinth is meant to be the spiritual successor to del Toro's earlier film, The Devil's Backbone. While the latter was a boys' movie the former is meant to be its sister parallel, a female heroine fighting against patriarchal authoritarianism. (Source)

The part of Ofelia was first written as an eight- or nine-year-old girl. But when Ivana Baquero read, del Toro's wife was brought to tears and del Toro was willing to do some rewriting to make it work for her. (Source)

During an early screening of the film, del Toro sat next to the master of horror, Stephen King. Del Toro said that when King squirmed during the Pale Man scene, it was one of the best moments of his life. (Source)