- Career Resurrection: While Death Wish (2018) was a modest success, The House With a Clock in Its Walls ended up beating Hostel as Eli Roth's most successful film both critically and commercially.
- Fake Nationality: Aussie Cate Blanchett as Florence Zimmerman, who speaks with an American accent but is presumably French.
- Though she lived in Paris at some point, it was never specified she was French. She could have simply moved there. It's implied she's a Jew and her last name is German.
- Genre Adultery: While Eli Roth is known as a Splatter Horror director, this film is more of a gothic-horror family fantasy film, and thus way Lighter and Softer than Roth's other horror films.