During the course of filming, Daniel Radcliffe matured a lot physically. In an interview, Mike Newell remarked "I've just been working on a scene which we shot in our first week, and Dan still looks like the little kid that he was in Sorcerer's Stone. Now, eleven months later, he doesn't look like that at all."
While filming his scenes as Professor Dumbledore, Sir Michael Gambon wore street clothes under his flimsy costume. He also kept his cigarettes tucked into his socks.
Mike Newell only received $1 million to direct (whereas Chris Columbus received $10 million, plus a percentage of the gross, to direct Harry Potter and the Sorcerer's Stone (2001)).
Final Harry Potter movie to feature scenes filmed at the University of Oxford. Oxford inspired much of the architecture of Hogwarts, including the Great Hall.